Method for detecting aldehyde ketone compounds in air

Abstract

The invention belongs to the field of ambient air quality detection, and particularly relates to a method for detecting aldehyde ketone compounds in air. Comprising the following steps: collecting a blank sample gas and a sample gas of a to-be-detected sample subjected to pretreatment, placement and balance treatment by using a DNPH sampling tube to obtain a blank tube and a sample tube, eluting by using acetonitrile respectively, and fixing the volume to obtain a blank solution and a sample solution. Preparing standard working solutions with different concentrations, analyzing by using a high performance liquid chromatograph, detecting by using a diode array detector, and drawing a standard working curve. And analyzing the blank solution and the sample solution by using a high performance liquid chromatograph, calculating the difference value of the peak areas of the target objects in the blank solution and the sample solution, and combining with a corresponding standard working curve and a calculation formula to obtain the actual content of the 26 aldehyde ketone compounds in the sample to be detected after the background blank is deducted. According to the present invention, the simultaneous complete effective separation of the 26 aldehyde ketone compounds is achieved for the first time, and the quantitative analysis of the 26 aldehyde ketone compounds can be simultaneously completed in one analysis.

Description

Technical Field

[0001] The present invention belongs to the field of ambient air quality detection, in particular to the field of in-vehicle air quality detection, and specifically to a method for detecting aldehyde and ketone compounds in the air. Background Art

[0002] Aldehydes and ketones are among the major pollutants in indoor air. Most are irritants and toxic, can cause respiratory infections, and pose risks such as sensitization, carcinogenesis, and mutagenesis. The manufacturing process for automotive interior components uses a large amount of plastics, textiles, leather, rubber, foaming materials, inks, and coatings. These raw materials often contain aldehydes and ketones, or they produce aldehydes and ketones as byproducts due to production processes and other factors. After the finished parts are installed in the vehicle, these residues are gradually released over time, affecting the air quality inside the vehicle. Therefore, aldehydes and ketones have long been a key control item for domestic and international automakers and parts suppliers in their in-vehicle air quality management.

[0003] High-performance liquid chromatography (HPLC) is the most commonly used method for detecting aldehydes and ketones in both in-vehicle and ambient air due to its low detection limits, high sensitivity, and good accuracy. It can simultaneously analyze a variety of aldehydes and ketones, is easy to operate, and has low analysis costs. It is specified as a detection method in relevant domestic and international standards such as the international standard ISO 16000-3, the environmental standard HJ 683-2014, and the automotive industry standard HJ / T 400-2007. The recommended method is applicable to the analysis of 3 to 14 common aldehydes and ketones. However, there are far more than 14 common aldehyde and ketone pollutants in air; up to 26 are encountered in routine air quality testing. As the number of target analytes increases, several groups of common aldehyde and ketone compounds are difficult to separate simultaneously, including acrolein, acetone, and furfural; 2-butanone, n-butyraldehyde, and cyclopentanone; cyclohexanone, isovaleraldehyde, valeraldehyde, and glutaraldehyde; and o-, m-, and p-methylbenzaldehyde. High-performance liquid chromatography (HPLC) methods cannot effectively separate these target compounds, effectively quantifying them. Among these difficult-to-separate components, cyclopentanone (CAS. No. 120-92-3) is a common ketone compound with volatility and a distinctive odor. It is commonly used in polymer materials, pharmaceutical chemicals, and electronic appliances. Cyclopentanone is relatively low because its toxicity does not have relevant contact or occupational safety restrictions at home and abroad at present, therefore often used as environmentally friendly solvent and is applied to the production of various polymer materials, is a kind of common volatile residue, does not have the report of relevant detection method temporarily.But because there is certain special smell in cyclopentanone, has irritation and sensitization, residue has certain impact for interior air quality especially interior peculiar smell of vehicle, therefore is necessary to carry out accurate quantitative analysis.When adopting existing high performance liquid chromatography to carry out detection analysis, because the character of cyclopentanone is similar to 2-butanone, n-butyraldehyde, usually flow out altogether with these two kinds of materials, thereby affect the accuracy of testing result.In prior art, do not have and can accomplish simultaneously effectively separation and quantitative high performance liquid chromatography method to 26 kinds of aldehydes and ketones compounds, greatly limit the application of high performance liquid chromatography in multiple class aldehydes and ketones compounds analysis field, be the unresolved problem of current air quality detection field all the time.

[0004] In the field of air quality monitoring, aldehyde and ketone compounds can be detected using methods other than high-performance liquid chromatography (HPLC-MS), gas chromatography, and gas chromatography-mass spectrometry (GC-MS). Gas chromatography and GC-MS are less commonly used due to the thermal stability of aldehydes and ketones and their derivatives. Existing HPLC-MS methods are complex and require high analytical and maintenance costs, making them unsuitable for large-scale industrial applications and rapid screening of large sample batches. Therefore, developing an HPLC method capable of simultaneously analyzing as many aldehyde and ketone compounds as possible in air is of great practical significance. Summary of the Invention

[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides a method for detecting aldehydes and ketones in the air, which expands the number of aldehydes and ketones that can be simultaneously detected and analyzed by high-performance liquid chromatography, and solves the problem that high-performance liquid chromatography cannot simultaneously separate and accurately quantify 26 common aldehydes and ketones in the field of air quality detection, affecting the accuracy and detection efficiency of the actual detection results, and limiting the application of high-performance liquid chromatography in the field of analysis of multiple types of aldehydes and ketones.

[0006] To solve the above problems, the present invention provides a method for detecting aldehydes and ketones in the air, comprising the following steps: S1. Provide the sample to be tested and place it for later use after pretreatment; S2. Before starting the test, collect a background blank sample or collect a blank sample simultaneously with the sample. Use a sampling tube coated with 2,4-dinitrophenylhydrazine to collect a blank sample of aldehydes and ketones to obtain a blank tube; S3. The pre-treated sample to be tested is placed after equilibrium treatment and then the sample gas of aldehyde and ketone compounds is collected using a sampling tube coated with 2,4-dinitrophenylhydrazine to obtain a sample tube; S4. Elute the blank tube and sample tube with acetonitrile, and then adjust the volume to obtain blank solution and sample solution; S5. Prepare mixed standard working solutions of 26 aldehyde-ketone-DNPH derivatives at different concentrations and analyze them using high-performance liquid chromatography (HPLC) supplemented with a diode array detector (DAD). Plot a standard working curve and obtain the regression equation corresponding to each target compound. The aldehyde and ketone compounds are the following 26 kinds: Formaldehyde, acetaldehyde, furfural, acrolein, acetone, propionaldehyde, crotonaldehyde, methacrolein, 2-butanone, n-butyraldehyde, cyclopentanone, benzaldehyde, isovaleraldehyde, glutaraldehyde, cyclohexanone, valeraldehyde, o-methylbenzaldehyde, m-methylbenzaldehyde, p-methylbenzaldehyde, 4-methyl-2-pentanone, hexanal, 2,5-dimethylbenzaldehyde, heptaldehyde, octanal, nonanal, decanal; S6. The blank solution and the sample solution were analyzed using a high performance liquid chromatograph and detected using a diode array detector to obtain the peak area corresponding to each target in the blank solution and the sample solution. The peak area corresponding to each target in the sample solution was subtracted from the peak area corresponding to each target in the blank solution and the peak area was substituted into the corresponding standard curve regression equation to obtain the actual content of the 26 aldehyde and ketone compounds in the sample tube after deducting the background blank. The content of the 26 aldehyde and ketone compounds in the sample to be tested was then converted using the formula; The analysis conditions of the HPLC analysis method are: Chromatographic column: First chromatographic column: CNW Athena C18 column, 4.6 mm × 250 mm, 5 µm, Secondary column: GL Sciences ODS-P C18 column, 4.6 mm × 250 mm, 5 µm, The first chromatographic column and the second chromatographic column are sequentially connected in series; Mobile phase: Phase A is water, phase B is acetonitrile; Injection volume: 12 μL; Flow rate: 1.0 mL / min; Column temperature: 30~40℃; Diode array detector, detection wavelength is 367nm; The gradient elution program is as follows: 0 min, the proportion of mobile phase A was 40%, and the proportion of mobile phase B was 60%; 25 min, the proportion of mobile phase A was 35%, and the proportion of mobile phase B was 65%; 30 min, the proportion of mobile phase A was 0%, and the proportion of mobile phase B was 100%; 40 min, the proportion of mobile phase A was 0%, and the proportion of mobile phase B was 100%; 45 min, the proportion of mobile phase A was 40%, and the proportion of mobile phase B was 60%.

[0007] Optionally, the pretreatment temperature is a constant temperature of 20-25° C., the relative humidity is a constant humidity of 40-60%, and the pretreatment time is 6 hours to 7 days.

[0008] Optionally, the balancing process adopts a 1 cubic meter test chamber sampling method, wherein the 1 cubic meter test chamber sampling method collects a background blank sample before starting the test; Alternatively, the balancing treatment adopts a sampling bag sampling method, wherein a blank bag is taken for parallel testing, and a blank sample is collected synchronously with the sample; Alternatively, the balancing process adopts a whole vehicle sampling method, and the whole vehicle sampling method collects blank samples synchronously with the samples.

[0009] Optionally, the equilibrium processing temperature of the 1 cubic meter test chamber sampling method and the sampling bag sampling method is 60°C~65°C, and the equilibrium processing temperature of the whole vehicle sampling method is 23.0°C~25.0°C.

[0010] Optionally, the elution and volume determination include the following steps: Acetonitrile was used to elute the blank tube and the sample tube respectively in the opposite direction of the sampling direction, the eluted eluate was collected in a volumetric flask, and the volume was fixed with acetonitrile to obtain a blank solution and a sample solution.

[0011] Optionally, in the elution step, the speed at which acetonitrile is eluted in the blank tube and the sample tube in the opposite direction of the sampling direction is 2-3 mL / min.

[0012] Optionally, the 26 aldehyde-ketone-DNPH derivative mixed standard working solutions are prepared from a cyclopentanone-DNPH standard stock solution and a mixed standard of 25 aldehyde-ketone-DNPH derivative compounds.

[0013] Optionally, the cyclopentanone-DNPH standard stock solution comprises the following preparation steps: Prepare hydrochloric acid buffer solution; Weigh 2,4-dinitrophenylhydrazine into a volumetric flask, add acetonitrile and ultrasonically vibrate to dissolve; Add hydrochloric acid buffer solution to the above solution and mix well; Weigh cyclopentanone and add it to the above solution for derivatization reaction so that the molar ratio of 2,4-dinitrophenylhydrazine to cyclopentanone is greater than 2:1. After adjusting the volume with acetonitrile, shake the reaction in a water bath at 25-45°C for 10-50 minutes.

[0014] Optionally, during the derivatization reaction process for preparing the cyclopentanone-DNPH standard stock solution, the concentration of the hydrochloric acid buffer solution is 1-2 mol / L.

[0015] Optionally, the concentration of the mixed standard working solution of the 26 aldehydes and ketones-DNPH derivatives is 0.006 μg / mL to 6 μg / mL.

[0016] Optionally, the actual contents of the 26 aldehyde and ketone compounds in the sample tube after deducting the background blank are calculated according to the regression equation of the standard curve, and then the actual contents of the 26 aldehyde and ketone compounds in the sample to be tested are calculated according to the following formula:

[0017] Where: G ——Volatilization amount of the sample to be tested, unit: μg / m3 ; W ——The amount of compound captured in the sample tube after deducting the background blank, calculated by the regression equation of the standard curve, unit: μg / mL; e ——Constant volume of acetonitrile eluent, mL; Q ——Convert the amount of gas collected in the sample tube according to 23°C and 101.3 KPa. The unit is L. The specific conversion formula is as follows:

[0018] in: V ——Actual sampling volume, unit: L; T ——Absolute temperature of the sampling point during sampling, unit: K; T x — absolute temperature at the reference state, 296.15 K; P ——The atmospheric pressure at the sampling point during sampling, unit: kPa; P x ——Atmospheric pressure under reference conditions, 101.3 kPa.

[0019] The beneficial effects of the present invention are as follows: compared with the prior art, the method for detecting aldehyde and ketone compounds in the air developed by the present invention uses a high performance liquid chromatography as an analytical instrument equipped with a diode array detector (DAD). Through the development of a specific chromatographic column system, the selection of a coordinated mobile phase system, and the development of a specific gradient elution program, the three interact, influence, and cooperate with each other, thereby overcoming the shortcomings of each technical feature when applied alone. At the same time, combined with the development of other analytical parameters, the method successfully achieves complete and effective separation of 26 aldehyde and ketone compounds in the air at the same time, solving the problem of simultaneous separation and quantification of several groups of aldehyde and ketone compounds that have long plagued the field of air quality detection and are difficult to separate simultaneously. In particular, the method effectively separates a group of easily co-eluted substances, namely cyclopentanone, 2-butanone, and n-butyraldehyde, solving the problem that these three substances interfere with each other and cannot be accurately quantified in actual application scenarios, thus filling the gap between high performance liquid chromatography and chromatographic analysis. The blank of cyclopentanone detection by chromatography can simultaneously complete the complete and effective separation and accurate quantification of 26 aldehyde and ketone compounds in a single analysis, eliminating the need for multiple analyses, thereby improving analysis efficiency, simplifying equipment operation and maintenance, and reducing analysis costs. Furthermore, the detection limit of each target object in the detection method provided by the present invention is 0.0003-0.0028 μg / mL, which is lower than the detection limit and better sensitivity compared with the detection method using the same equipment in the prior art. After multiple analyses, the relative standard deviation (RSD) of each target object is 0.09%-1.68%, indicating good method precision. Furthermore, the mobile phase system used has low toxicity, making the method more suitable for analysis in industrial laboratories and on-site, as well as for rapid screening of large quantities of samples. Application scenarios include atmospheric environmental quality detection, indoor air quality detection, especially in-vehicle air quality detection, and other fields. The method has a wide range of applications and high practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The liquid chromatograms of 26 aldehyde and ketone compounds obtained by the analytical method in Example 1 are shown.

[0021] Figure 2 3 is the blank sample solution chromatogram.

[0022] Figure 3 This is the chromatogram of the blank in Example 3 spiked with standard working solution (theoretical concentration 0.6 μg / mL).

[0023] Figure 4 This is the chromatogram obtained by the analytical method in Example 9.

[0024] Figure 5 This is the chromatogram obtained by the analytical method in Example 10.

[0025] Figure 6 This is the chromatogram obtained by the analytical method in Example 11.

[0026] Figure 7This is the chromatogram obtained by the analytical method in Example 12.

[0027] Figure 8 This is the chromatogram obtained by the analytical method in Example 13.

[0028] Figure 9 This is the chromatogram obtained by the analytical method in Example 14.

[0029] Figure 10 This is the chromatogram obtained by Scheme 1 in Comparative Example 1.

[0030] Figure 11 This is the chromatogram obtained from Scheme 2 in Comparative Example 1.

[0031] Figure 12 This is the chromatogram obtained in Scheme 3 in Comparative Example 1.

[0032] Figure 13 This is the chromatogram obtained by Scheme 1 in Comparative Example 2.

[0033] Figure 14 This is the chromatogram obtained by Scheme 2 in Comparative Example 2.

[0034] Figure 15 This is the chromatogram obtained in Scheme 3 in Comparative Example 2.

[0035] Figure 16 This is the chromatogram obtained by Scheme 1 in Comparative Example 3.

[0036] Figure 17 The chromatogram obtained by scheme 1 in comparative example 3 is attached. Figure 16 A partial enlarged view of .

[0037] Figure 18 This is the chromatogram obtained by method A in scheme 2 in comparative example 3.

[0038] Figure 19 This is the chromatogram obtained by method B in scheme 2 in comparative example 3.

[0039] Figures 1 to 19 The aldehyde and ketone compounds shown in the accompanying drawings are as follows: 1. Formaldehyde; 2. Acetaldehyde; 3. Furfural; 4. Acrolein; 5. Acetone; 6. Propanal; 7. Crotonaldehyde; 8. Methacrolein; 9. 2-Butanone; 10. Butyraldehyde; 11. Cyclopentanone; 12. Benzaldehyde; 13. Isovaleraldehyde; 14. Glutaraldehyde; 15. Cyclohexanone; 16. Valeraldehyde; 17. o-Tolualdehyde; 18. m-Tolualdehyde; 19. p-Tolualdehyde; 20. 4-Methyl-2-pentanone; 21. Hexanal; 22. 2,5-Dimethylbenzaldehyde; 23. Heptanal; 24. Octanal; 25. Nonanal; 26. Decanal. DETAILED DESCRIPTION

[0040] To make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0041] As used herein, the terms "comprises," "including," "having," "containing" or any other variations thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises a listed element is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0042] "Optional" or "either" means that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where the event occurs and instances where it does not.

[0043] The indefinite articles "a" and "an" before the elements or components of the present invention do not limit the quantity requirement (i.e., the number of times the elements or components appear). Therefore, "a" or "an" should be interpreted as including one or at least one, and elements or components in the singular also include plural forms, unless the quantity clearly refers to only the singular form.

[0044] The terms "one embodiment," "some embodiments," "exemplarily," "specific examples," or "some examples" used in the present invention mean that a specific feature, structure, material, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment or example of the present invention. In this document, the exemplary expressions of the above terms do not necessarily refer to the same embodiment or example.

[0045] The numerical range described in the present invention includes not only the point values ​​listed in the embodiments, but also any point values ​​not listed between the numerical ranges described in the present invention. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0046] In the following examples, unless otherwise specified, all reagents and consumables were purchased from conventional reagent manufacturers in the field.

[0047] In the detection of in-car air quality, in addition to formaldehyde, acetaldehyde and acrolein defined in the Guidelines for the Assessment of In-Car Air Quality GB / T 27630-2011, common aldehyde and ketone compounds in the car also include: acetone, furfural, propionaldehyde, crotonaldehyde, 2-butanone, methacrolein, n-butyraldehyde, cyclopentanone, benzaldehyde, cyclohexanone, isovaleraldehyde, valeraldehyde, o-methylbenzaldehyde, glutaraldehyde, m-methylbenzaldehyde, p-methylbenzaldehyde, 4-methyl-2-pentanone, hexanal, 2,5-dimethylbenzaldehyde, heptaldehyde, octanal, nonanal and decanal. These substances appear frequently in daily detection, have a greater impact on the physical and mental health of drivers and passengers and the odor in the car, and are also the focus of some high-end car manufacturers. Therefore, the detection method of the present invention is particularly suitable for the detection of various types of aldehyde and ketone compounds in the air inside the car, and the following examples will mainly focus on the specific method of in-car air quality detection.

[0048] The present invention provides a method for detecting aldehyde and ketone compounds in the air, comprising the following steps: S1. Provide the sample to be tested and place it for later use after pretreatment; S2. Before starting the test, collect a background blank sample or collect a blank sample simultaneously with the sample. Use a sampling tube coated with 2,4-dinitrophenylhydrazine to collect a blank sample of aldehydes and ketones to obtain a blank tube; S3. The pre-treated sample to be tested is placed after equilibrium treatment and then the sample gas of aldehyde and ketone compounds is collected using a sampling tube coated with 2,4-dinitrophenylhydrazine to obtain a sample tube; S4. Elute the blank tube and sample tube with acetonitrile, and then adjust the volume to obtain blank solution and sample solution; S5. Prepare mixed standard working solutions of 26 aldehyde-ketone-DNPH derivatives at different concentrations and analyze them using high-performance liquid chromatography (HPLC) supplemented with a diode array detector (DAD). Plot a standard working curve and obtain the regression equation corresponding to each target compound. The aldehyde and ketone compounds are the following 26 kinds:

[0049] S6. The blank solution and the sample solution were analyzed using a high performance liquid chromatograph and detected using a diode array detector to obtain the peak area corresponding to each target in the blank solution and the sample solution. The peak area corresponding to each target in the sample solution was subtracted from the peak area corresponding to each target in the blank solution and the peak area was substituted into the corresponding standard curve regression equation to obtain the actual content of the 26 aldehyde and ketone compounds in the sample tube after deducting the background blank. The content of the 26 aldehyde and ketone compounds in the sample to be tested was then converted using the formula; Volatile aldehyde and ketone pollutants in vehicle interior air primarily originate from automotive interior components and materials in the passenger compartment and luggage compartment. In the field of in-vehicle air quality testing, the production, environmental, and transportation conditions of automotive interior materials and components vary. Pre-conditioning samples at a specified temperature and humidity for a specified period of time before testing helps stabilize the samples and better ensure the parallelism and repeatability of test results.

[0050] In some specific embodiments, the pretreatment temperature is a constant temperature of 20~25°C. As an example, the pretreatment temperature of the sample can also be 21°C, 22°C, 23°C, or 24°C, as long as the pretreatment temperature is within the range.

[0051] In some specific embodiments, the relative humidity of the pretreatment placement is a constant humidity of 40~60%. As an example, the pretreatment placement humidity can also be 42%, 45%, 46%, 48%, 50%, 51%, 53%, 55%, or 58%, as long as the pretreatment placement humidity is within the range.

[0052] In some specific embodiments, the pretreatment placement time is 6 hours to 7 days. As an example, the pretreatment placement time can also be 1 day, 2 days, 3 days, 4 days, 5 days, or 6 days, as long as the pretreatment placement time is within the range.

[0053] The principle of high-performance liquid chromatography (HPLC) for detecting aldehydes and ketones in air is to collect a gas sample through a sampling tube coated with 2,4-dinitrophenylhydrazine (DNPH sampling tube). The aldehydes and ketones in the air react chemically with 2,4-dinitrophenylhydrazine (DNPH, CAS. No. 119-26-6) in the sampling tube to produce corresponding hydrazone derivatives, which absorb at specific wavelengths. After elution with a certain amount of acetonitrile, the corresponding hydrazone derivatives are detected using a UV detector or a diode array detector (DAD), thereby determining the corresponding aldehyde and ketone compound content. (In this disclosure, the target compound of the HPLC analysis method is described as "aldehyde and ketone compounds").

[0054] In some specific embodiments, the balancing process adopts a 1 cubic meter test chamber sampling method, and the sampling process of the 1 cubic meter test chamber sampling method specifically includes the following steps: Sampling of automotive interior parts for the entire vehicle, sampling of interior materials 1kg or 1m 2, or sampling according to the company standards of the automobile manufacturer. Before testing, remove the outer packaging of the sample and pre-condition it in a constant temperature and humidity room at a temperature of (23±2)℃ and a relative humidity of (50±5)% for 7 days before testing.

[0055] After aging in a 1 cubic meter test chamber, the background total hydrocarbon concentration in the chamber was continuously monitored using an online FID (needed to be less than 1.0 ppm). The test chamber equilibrium treatment conditions were set as follows: temperature 65°C, relative humidity 5%, and gas exchange rate 0.4h -1 After all parameters are stable, background blank tubes are collected. DNPH sampling tubes are used to collect background blanks of 26 aldehyde and ketone compounds. The sampling parameters are: 1L / min, and 60L of cabin gas is collected.

[0056] After the blank sample is collected, place the sample in the cabin, quickly close the cabin door, and start the test.

[0057] The sample sampling time is 3 hours after the sample is placed in the chamber. The sample gas is collected using a DNPH sampling tube. The sampling parameter is: 1L / min, and 60L of chamber gas is collected.

[0058] In some specific embodiments, the balancing process adopts a sampling bag sampling method, and the sampling process of the sampling bag sampling method specifically includes the following steps: Automobile interior parts are generally sampled for the entire vehicle, and interior materials are generally sampled for 1kg or 1m 2 , or sampling according to the corporate standards of each automobile manufacturer. Before testing, remove the sample packaging and precondition it in a constant temperature and humidity room at (23±2)°C and (50±5)% for 1-7 days before testing. Alternatively, the preconditioning time must be based on the requirements of the corporate standards of each automobile manufacturer.

[0059] The sampling bags are polyvinyl fluoride sampling bags, usually with sizes of 500 L, 1000 L or 2000 L, and other specifications and sizes can also be used.

[0060] Before sampling, the sampling bag should be cleaned and aged. This can be done by placing the bag with the inside facing out, securing it to a bracket, and placing it in a constant-temperature chamber for 24 hours at 80°C. The sample should be placed in the aged bag, sealed with sealing strips, and evacuated using a diaphragm vacuum pump to verify airtightness. After leak testing, the bag should be degassing with high-purity nitrogen. Fill the bag with nitrogen to 50% of its volume, shake well, and then remove the nitrogen. Repeat this process twice. After degassing, fill the bag with nitrogen to an accurate 50% of its volume. The bag should be moved to a constant-temperature chamber and equilibrated at 60-65°C for 2 hours. Aldehydes and ketones should then be sampled using a DNPH sampling tube at a sampling rate of 1 L / min, collecting 60 L of bag gas.

[0061] The background blank bag was tested in parallel with the sample, and the sampling process and parameters were the same as those of the sample, except that no sample was placed in it.

[0062] In some specific embodiments, the balancing process adopts a whole vehicle sampling method, and the sampling process of the whole vehicle sampling method specifically includes the following steps: The inspected vehicles must generally meet the test date within 28 days ± 5 days from the date of production.

[0063] Before testing, adjust the sampling parameters of the vehicle environmental chamber to meet the following conditions: Temperature: 23.0℃~25.0℃; Relative humidity: 50%±10%.

[0064] Vehicle preparation phase: Place the vehicle under test in the whole-vehicle VOC sampling chamber. Remove any coverings on the interior components (such as plastic film used to protect seats and carpets before leaving the factory) and move them outside the chamber. Fully open all windows and doors of the vehicle under test and allow it to sit for 6 hours.

[0065] During the final hour of the preparatory phase, use a DNPH sampling tube to collect a blank sample from the environmental chamber. The sampling point is 0.5 meters from the vehicle body, which is consistent with the driver and passenger breathing zone height (1.2 meters to 1.5 meters). Collect one DNPH tube as the environmental blank (to measure the environmental background value before the test, which is not included in the final result calculation).

[0066] Vehicle closure phase: Use brackets to arrange sampling pipelines, and the number of sampling points is determined by the effective volume of the passenger compartment of the inspected vehicle and the specific conditions of the inspected vehicle. a) M1 * One measurement point is arranged for vehicles of this type, located at the intersection of the line connecting the front seat headrests and the center axis of the vehicle compartment (the sliding front seat should slide to the rearmost position of the slide rail); b) M2 ** For vehicles of this type, there should be no less than 2 measuring points, evenly distributed along the center axis of the carriage; c) M3 *** For Category M vehicles, there shall be no less than 3 measuring points (for Category M vehicles that are double-deck or articulated buses, there shall be 6 measuring points), evenly spaced along the center axis of the carriage; d) N **** For vehicles of this type, one measurement point is arranged, which is located at the intersection of the line connecting the seat headrests in the front cockpit and the center axis of the vehicle.

[0067] Note: * Category M1 vehicles are motor vehicles with at least four wheels and designed to carry passengers. They are passenger vehicles with no more than nine seats, including the driver's seat.

[0068] ** M2 vehicles are motor vehicles with at least four wheels and designed to carry passengers. They must have more than nine seats, including the driver's seat, and a maximum design gross vehicle mass not exceeding 5,000 kg.

[0069] *** M3 vehicles are motor vehicles with at least four wheels and designed to carry passengers. They must have more than nine seats, including the driver's seat, and a maximum design gross vehicle mass exceeding 5,000 kg.

[0070] **** Category N vehicles are motor vehicles with at least four wheels used for carrying cargo.

[0071] Each sampling point can be equipped with four different types of sampling tubes to collect different types of samples. The inlet should be at a height consistent with the driver's breathing zone (1.2 to 1.5 meters), and the outlet should be sealed with a plug to prevent leakage of in-vehicle gas through the sampling tubes. The tubes should be appropriately routed from the passenger compartment without compromising the integrity and sealing of the vehicle.

[0072] Completely close all windows and doors of the vehicle under inspection, and let it stand for 16 hours while balancing.

[0073] Sample collection phase: Connect the DNPH sampling tube to the outlet of the sampling conduit and collect two DNPH tubes; record the condition of the inspected vehicle, sampling date, time, location, atmospheric pressure, temperature, relative humidity, airflow velocity, etc.; sample the background blank sample at the same time, the sampling point is 0.5m from the vehicle body, the height is consistent with the breathing zone height of the driver and passengers (1.2m~1.5m), and collect one DNPH tube.

[0074] The sampling parameters of the DNPH blank tube and sample tube are: sampling flow rate is 1L / min, and 60L of gas is collected.

[0075] In some specific embodiments, the elution and volume determination comprises the following steps: Acetonitrile was used to elute the blank tube and the sample tube respectively in the opposite direction of the sampling direction, and the eluted eluate was collected in a volumetric flask, and finally the volume was fixed with acetonitrile to obtain a blank solution and a sample solution.

[0076] In some specific embodiments, the acetonitrile is eluted from the blank tube and the sample tube in the direction opposite to the sampling direction at a rate of 2 to 3 mL / min. The rate of acetonitrile elution from the sampling tube is controlled to fully elute the adsorbed and coated chemical substances in the sampling tube and transfer them to the volumetric flask.

[0077] In some specific embodiments, the 26 aldehyde-ketone-DNPH derivative mixed standard working solution is prepared from a cyclopentanone-DNPH standard stock solution and a mixed standard solution of 25 aldehyde-ketone-DNPH derivative compounds. The 25 aldehyde-ketone-DNPH derivative mixed standard solution is a commercially available custom mixed standard solution containing the remaining 25 aldehyde-ketone-DNPH derivative compounds of the present invention, excluding the cyclopentanone-DNPH derivatives, at a concentration of 15 mg / L for each target compound, dissolved in acetonitrile. Since no standard samples of cyclopentanone-DNPH derivatives are available, they must be prepared in-house or custom-made.

[0078] In some specific embodiments, the cyclopentanone-DNPH standard stock solution comprises the following preparation steps: Prepare hydrochloric acid buffer solution; Weigh 2,4-dinitrophenylhydrazine into a volumetric flask, add acetonitrile and ultrasonically vibrate to dissolve; Add hydrochloric acid buffer solution to the above solution and mix well; Weigh cyclopentanone and add it to the above solution for derivatization reaction so that the molar ratio of 2,4-dinitrophenylhydrazine to cyclopentanone is greater than 2:1. After adjusting the volume with acetonitrile, shake the reaction in a water bath at 25-45°C for 10-50 minutes.

[0079] The above preparation steps can be used to obtain a cyclopentanone-DNPH standard stock solution, which can then be diluted to an appropriate concentration according to actual application requirements.

[0080] In some specific embodiments, during the derivatization reaction to prepare the cyclopentanone-DNPH standard stock solution, the concentration of the hydrochloric acid buffer solution is 1-2 mol / L. The primary purpose of the hydrochloric acid buffer solution is to adjust the acidity during the derivatization reaction, maintaining an acidic environment to facilitate a rapid and sufficient reaction between the aldehyde and ketone compounds and DNPH. Reference is made to prior art documents related to the preparation of aldehyde and ketone derivative compounds. During the derivatization reaction, an acidity of 1-2 mol / L is suitable for the hydrochloric acid buffer solution.

[0081] The preparation process of the cyclopentanone-DNPH standard stock solution is the preparation process used in the present invention. Other preparation methods can also use or customize commercial standards to achieve the same purpose.

[0082] In some specific embodiments, the concentration of the mixed standard working solution of the 26 aldehydes, ketones, and DNPH derivatives is 0.006 μg / mL to 6 μg / mL. As an example, the concentration of the mixed standard working solution of the 26 aldehydes, ketones, and DNPH derivatives can also be 0.01 μg / mL, 0.02 μg / mL, 0.05 μg / mL, 0.1 μg / mL, 0.2 μg / mL, 0.4 μg / mL, 0.5 μg / mL, 1.0 μg / mL, 1.5 μg / mL, 2.0 μg / mL, 3.0 μg / mL, 3.5 μg / mL, 4.0 μg / mL, 5.0 μg / mL, and 5.5 μg / mL. Since this embodiment is mainly used for the analysis and testing of aldehydes and ketones that may be emitted from automotive interior materials and parts, the concentration range of the target working solution is adaptively illustrated. If the method of this embodiment is to be used for the analysis of other materials and environments, it can be expanded accordingly based on the actual sample and environmental conditions.

[0083] In some specific embodiments, the analysis conditions of the high performance liquid chromatography analysis method are: Chromatographic column: First chromatographic column: CNW Athena type (C18, 4.6 mm×250 mm, 5 µm), Second chromatographic column: GL Sciences ODS-P (C18, 4.6 mm × 250 mm, 5 µm), The first chromatographic column and the second chromatographic column are sequentially connected in series; Mobile phase: Phase A is water, phase B is acetonitrile; Injection volume: 12 μL; Flow rate: 1.0 mL / min; Column temperature: 30~40℃; Diode array detector, detection wavelength is 367nm; The gradient elution program is as follows:

[0084] The key point and difficulty of the present invention lies in achieving the technical effect of simultaneously and effectively separating and accurately quantifying 26 aldehyde and ketone compounds through the development of a high performance liquid chromatography analysis method.

[0085] High performance liquid chromatography is the most commonly used detection method for the analysis of aldehydes and ketones, and reversed-phase bonded phase chromatography is generally used for analysis.

[0086] The separation ability of the chromatographic column plays a vital role in the separation of the target. Reversed-phase chromatography generally selects a porous microparticle silica gel carrier, which is then activated with acid and reacted with a silanization reagent containing an alkyl chain (C4, C8, C18) or a phenyl group to generate a non-polar stationary phase with an alkyl or phenyl surface, which is suitable for the separation of non-polar, polar or ionic compounds.

[0087] In this example, a CNW Athena (C18, 4.6 mm × 250 mm, 5 µm) and a GL Sciences ODS-P (C18, 4.6 mm × 250 mm, 5 µm) column were connected in series to form the analytical column system. Both columns are C18-bonded reversed-phase columns suitable for the separation of polar substances such as aldehydes and ketones.

[0088] Although both columns are C18 reversed-phase columns, their separation characteristics for aldehydes and ketones differ significantly, and the elution times of different aldehydes and ketones vary somewhat under the same analytical conditions. Comparative experiments show that using either column individually, whether using a water-acetonitrile-tetrahydrofuran ternary mobile phase or a water-acetonitrile binary mobile phase, is insufficient for the complete simultaneous separation of all 26 aldehydes and ketones. By combining these two columns, leveraging their respective characteristics and developing additional analytical parameters, the shortcomings of these two columns when used alone have been addressed, enabling the effective and accurate simultaneous separation and quantification of all 26 aldehydes and ketones.

[0089] The series combination of chromatographic columns, drawing on the principles of two-dimensional chromatography, can improve the theoretical plate efficiency to increase peak capacity, thereby improving the separation of the target. However, the series combination is different from the modulation and cutting function of two-dimensional chromatography. After the first separation through the first chromatographic column, all samples enter the second chromatographic column for re-separation. The different characteristics of each chromatographic column may cause the separated substances with similar properties to merge and co-elute again. Therefore, in addition to selecting suitable chromatographic columns and utilizing their respective characteristics for analysis, it is also necessary to develop a suitable elution system and gradient elution program.

[0090] In this example, a water-acetonitrile binary mobile phase system was selected as the elution system. This water-acetonitrile binary mobile phase system is the most commonly used elution system for the analysis of aldehydes and ketones by high-performance liquid chromatography, but no analytical method in the prior art has been able to effectively separate and accurately quantify 26 aldehydes and ketones using this system as an elution system.

[0091] Therefore, in the prior art, there is an application of adding a third phase to this binary system to change the performance of the elution system to better improve the separation degree of each target. The water-acetonitrile-tetrahydrofuran ternary mixed mobile phase system was developed from this, but there are still certain deficiencies in its application process. Some substances with difficult-to-separate components cannot be effectively separated at the same time. Tetrahydrofuran is a commonly used dipolar solvent. The use of tetrahydrofuran can significantly change the performance parameters of the mobile phase system, but it is relatively toxic and belongs to the Class 2B carcinogen in the carcinogen list published by the World Health Organization's International Agency for Research on Cancer. Since the addition of tetrahydrofuran has a certain effect on the noise of the baseline, the baseline noise of the ternary mixed system is slightly larger than that of the binary system. Tetrahydrofuran is corrosive to a certain extent, and long-term use may reduce the service life of the quaternary pump components and pipelines in high-performance liquid chromatography. Since the ternary mobile phase system involves the problem of uniform mixing of the mobile phase, long-term analysis may cause retention time deviation, and the requirements for quality control are higher. Therefore, under the premise of being able to effectively separate and accurately quantify 26 aldehyde and ketone compounds at the same time, the use of the water-acetonitrile binary mobile phase system is given priority.

[0092] In this example, a specially developed gradient elution procedure was used to separate the target compounds. In addition to the mobile phase system, the elution procedure is another crucial factor influencing the resolution of the target compounds. The gradient elution ratio changes in real time over time, and the system's performance parameters also change in real time, affecting the distribution equilibrium of solute molecules between the stationary phase and the mobile phase of the chromatographic column. This causes solute molecules of different polarities to elute and be detected by the detector at different time periods. Even slight differences in the mobile phase system and elution procedure can lead to changes in the system's performance parameters, affecting the resolution of the target compounds.

[0093] In this embodiment, the column temperature is preferably 40°C. The column temperature has a certain influence on the peak shape, separation, and retention time of each target on the chromatogram. According to experimental results, a column temperature range of 30°C to 40°C can meet technical requirements. Combined with routine analytical testing, 40°C is preferably used as the analytical column temperature.

[0094] In this embodiment, the flow rate is selected as 1.0 mL / min. The flow rate is generally selected considering the chromatographic column type and sample type. Increasing the flow rate can shorten the analysis time but will reduce the separation and affect the peak shape. Too low a flow rate will extend the analysis time. Therefore, after experiments, a flow rate of 1.0 mL / min is more appropriate.

[0095] In this embodiment, the injection volume is selected as 12 μL. The injection volume is generally adjusted according to the chromatographic column type and sample to obtain a better response and a lower signal-to-noise ratio. After experiments, the present invention selects 12 μL as the injection volume, and other suitable injection volumes can also be selected.

[0096] In this embodiment, the sample to be analyzed is separated by HPLC and then detected by a diode array detector (DAD). A diode array detector (DAD) is typically used for HPLC analysis of aldehydes and ketones. This type of UV absorption detector utilizes a deuterium lamp as a light source, resulting in high analytical sensitivity. Derivatized aldehydes and ketones, after DNPH derivatization, absorb ultraviolet light at specific wavelengths, commonly 360 nm or 367 nm. While 367 nm is selected as the detector's absorption signal wavelength in this invention, 360 nm can also be selected.

[0097] In this embodiment, through the development of a specific chromatographic column system, the selection of a coordinated mobile phase system, and the development of a specific gradient elution program, the three interact, influence, and cooperate with each other to overcome the shortcomings of each technical feature when applied alone. At the same time, combined with the development of other analytical parameters, the simultaneous, complete, and effective separation of 26 aldehyde and ketone compounds based on high-performance liquid chromatography was achieved for the first time, thereby achieving the technical goal of accurate quantitative analysis.

[0098] In some specific embodiments, the column temperature in the high performance liquid chromatography analysis method is 30° C., 32° C., 35° C., or 40° C. Generally, the temperature of the chromatographic column has a certain influence on the peak shape, separation degree, and retention time of each target on the chromatogram of the target. According to experiments and routine analytical tests, when other analytical parameters are the same, the column temperature range of 30° C. to 40° C. can achieve the purpose of effectively separating 26 aldehyde and ketone compounds simultaneously.

[0099] In some specific embodiments, the analysis conditions of the high performance liquid chromatography analysis method can also be: Chromatographic column: First chromatographic column: CNW Athena type (C18, 4.6 mm×250 mm, 5 µm), Secondary chromatographic column: GL Sciences ODS-P (C18, 4.6 mm × 250 mm, 5 µm), The first chromatographic column and the second chromatographic column are sequentially connected in series; Mobile phase: Phase A is water, phase B is acetonitrile; Injection volume: 12 μL; Flow rate: 1.0 mL / min; Column temperature: 40°C; Diode array detector, detection wavelength is 367nm; The gradient elution program is as follows:

[0100] In some specific embodiments, the analysis conditions of the high performance liquid chromatography analysis method can also be: Chromatographic column: First chromatographic column: CNW Athena type (C18, 4.6 mm×250 mm, 5 µm), Secondary chromatographic column: GL Sciences ODS-P (C18, 4.6 mm × 250 mm, 5 µm), The first chromatographic column and the second chromatographic column are sequentially connected in series; Mobile phase: Phase A is water, phase B is acetonitrile; Injection volume: 12 μL; Flow rate: 1.0 mL / min; Column temperature: 40°C; Diode array detector, detection wavelength is 367nm; The gradient elution program is as follows:

[0101] In some specific embodiments, the actual contents of the 26 aldehyde and ketone compounds in the sample tube after deducting the background blank are calculated according to the regression equation of the standard curve, and then the actual contents of the 26 aldehyde and ketone compounds in the sample to be tested are calculated according to the following formula:

[0102] Where: G ——Volatilization amount of the sample to be tested, unit: μg / m 3 ; W ——The amount of compound captured in the sample tube after deducting the background blank, calculated by the regression equation of the standard curve, unit: μg / mL; e ——Constant volume of acetonitrile eluent, mL; Q ——Convert the amount of gas collected in the sample tube according to 23℃ and 101.3KPa. The unit is L. The specific conversion formula is as follows:

[0103] in: V ——Actual sampling volume, unit: L; T ——Absolute temperature of the sampling point during sampling, unit: K; T x — absolute temperature at the reference state, 296.15 K; P ——The atmospheric pressure at the sampling point during sampling, unit: kPa; P x ——Atmospheric pressure under reference conditions, 101.3 kPa.

[0104] The solution of the present invention will be further described in detail below with reference to specific embodiments.

[0105] Main instruments and consumables: VCE 1000 classic / VOC 1000 1 cubic meter test chamber (Weiss, Germany); TESTA FID-2000MP / TESTA-2000MP-BMW Volatile Organic Compounds Online Monitoring System (Online FID, TESTA, Germany); V-BIR-56 / V-BIR-30 constant temperature test chamber (Dongguan Mingchi); GM-2 dual-purpose diaphragm vacuum pump (Tianjin Jinteng); VA-144 vehicle VOC environmental chamber (Dongguan Mingchi); S401 four-channel sampling pump (Ningbo Huance Experimental Equipment Co., Ltd.); GilAir Plus high-low constant-flow air sampling pump (SENSIDYNE, USA); Gilibrator-2 soap film flowmeter (SENSIDYNE, USA); Agilent 1260 Infinity high performance liquid chromatograph equipped with a diode array detector (DAD) (Agilent, USA); SK8210HP ultrasonic cleaner (Shanghai Kedao Ultrasonics); XS105DU electronic balance (Mettler, Switzerland); SHZ-C water bath constant temperature oscillator (Shanghai Bozhen Instrument); H18091C pipette (Eppendorf, Germany); DNPH sampling tube (Ningbo Huance Experimental Equipment Co., Ltd., Waters); Polyvinyl fluoride sampling bag (Tedlar sampling bag, Ningbo Huance Experimental Equipment Co., Ltd., 2000L).

[0106] Standard substances: A standard mixture of 25 aldehyde and ketone-DNPH derivative compounds (customized standard solution, each target compound concentration was 15 mg / L dissolved in acetonitrile, containing the following DNPH derivatives of aldehydes and ketones: formaldehyde, acetaldehyde, furfural, acrolein, acetone, propionaldehyde, crotonaldehyde, methacrolein, 2-butanone, n-butyraldehyde, benzaldehyde, isovaleraldehyde, glutaraldehyde, cyclohexanone, valeraldehyde, o-methylbenzaldehyde, m-methylbenzaldehyde, p-methylbenzaldehyde, 4-methyl-2-pentanone, hexanal, 2,5-dimethylbenzaldehyde, heptanal, octanal, nonanal, and decanal) was purchased from Fint Standard. Cyclopentanone (98.77%), purchased from Dr. Ehrenstorfer; Hydrochloric acid (37%) was purchased from Jiangsu Qiangsheng Functional Chemical Co., Ltd.; 2,4-Dinitrophenylhydrazine (DNPH, ≥99.0%) was purchased from Yonghua Chemical Technology (Jiangsu) Co., Ltd.; Acetonitrile and tetrahydrofuran (chromatographic grade reagents, Shanghai Xingke High Purity Solvent Co., Ltd.); Water (ultrapure water, filtered by Molgene 1805V-UP ultrapure water instrument, meeting the requirements of laboratory first-class water); Chromatographic column: CNW Athena type (C18, 4.6 mm × 250 mm, 5 μm), Shanghai Anpu Laboratory Technology Co., Ltd. Chromatographic column: GL Sciences ODS-P type (C18, 4.6 mm×250 mm, 5 μm), Shimadzu Corporation, Japan.

[0107] Preparation of standard solution: 1. Preparation of cyclopentanone-DNPH standard stock solution: Preparation of hydrochloric acid buffer solution: Take 5 g of 37% hydrochloric acid in a 10 mL volumetric flask, add water to the volume and shake well to prepare a hydrochloric acid buffer solution with a concentration of about 5 mol / L; Add a small amount of acetonitrile to a 50mL brown volumetric flask. Weigh a certain amount of 2,4-dinitrophenylhydrazine (DNPH) into the flask and record the actual weight (accurate to 0.00001g). After ultrasonically dissolving as much as possible, add 10mL of hydrochloric acid buffer solution and mix thoroughly. Weigh a certain amount of cyclopentanone (accurate to 0.00001g) into the flask to make an excess of DNPH and a molar ratio (DNPH:aldehyde / ketone) greater than 2:1. Dose up to volume with acetonitrile and shake thoroughly in a 40°C water bath for 20 minutes (maintaining the actual concentration of the hydrochloric acid buffer during the derivatization reaction between 1 and 2 mol / L). This will produce a cyclopentanone-DNPH standard stock solution.

[0108] Transfer the above solution into a 1L brown volumetric flask, wash the 50mL volumetric flask with acetonitrile several times, combine the washings and add them to the 1L brown volumetric flask, and adjust the volume with acetonitrile to obtain the cyclopentanone-DNPH (grade I) standard stock solution; Use a pipette to take 50 mL of cyclopentanone-DNPH (Grade I) standard stock solution into a 500 mL brown volumetric flask, and dilute to volume with acetonitrile to obtain cyclopentanone-DNPH (Grade II) standard stock solution.

[0109] According to the above steps and calculation, the concentration of the cyclopentanone-DNPH standard stock solution used in the embodiment of the present invention (calculated as aldehydes and ketones) is: Cyclopentanone-DNPH (grade I) standard stock solution: 270.72857 mg / L; Cyclopentanone-DNPH (grade II) standard stock solution: 27.072857 mg / L; The standard stock solution was stored at 0-5°C.

[0110] The above cyclopentanone-DNPH standard stock solution preparation process is the preparation process used in the present invention. Other preparation methods can also use or customize commercial standards to achieve the same purpose.

[0111] 2. Preparation of mixed standard working solutions of 26 aldehydes, ketones and DNPH derivatives: A. Mixture of 25 aldehyde-ketone-DNPH derivatives (15 mg / L dissolved in acetonitrile); B. Cyclopentanone-DNPH (Grade II) standard stock solution (27.072857 mg / L dissolved in acetonitrile); Take a standard mixture of 25 aldehyde-ketone-DNPH derivatives at a concentration of 15 mg / L. Accurately pipette 0.8 μL, 8 μL, 40 μL, 80 μL, 200 μL, 400 μL, and 800 μL into seven 2 mL volumetric flasks, respectively. Next, take the cyclopentanone-DNPH (Grade II) standard stock solution at a concentration of 27.072857 mg / L. Accurately pipette 0.44 μL, 4.43 μL, 22.16 μL, 44.32 μL, 110.81 μL, 221.62 μL, and 443.25 μL into the seven 2 mL volumetric flasks corresponding to the above concentrations, from lowest to highest. Prepare 26 mixed standard working solutions of aldehydes, ketones, and DNPH derivatives using acetonitrile to volume. The concentrations of each substance are 0.006 μg / mL, 0.06 μg / mL, 0.3 μg / mL, 0.6 μg / mL, 1.5 μg / mL, 3 μg / mL, and 6 μg / mL, respectively. Store the standard working solutions at 0–5°C.

[0112] Example 1 Mixed standard working solutions of 26 aldehyde and ketone-DNPH derivatives at concentrations of 0.006 μg / mL, 0.06 μg / mL, 0.3 μg / mL, 0.6 μg / mL, 1.5 μg / mL, 3 μg / mL, and 6 μg / mL were analyzed according to the following analytical parameters: Liquid chromatography conditions: Chromatographic column: First chromatographic column: CNW Athena type (C18, 4.6 mm×250 mm, 5 µm), Secondary chromatographic column: GL Sciences ODS-P (C18, 4.6 mm × 250 mm, 5 µm), The chromatographic columns are connected in sequence; Mobile phase: Phase A is water, phase B is acetonitrile; Injection volume: 12 μL; Flow rate: 1.0 mL / min; Column temperature: 40°C; Diode array detector, detection wavelength is 367nm; The gradient elution program is as follows:

[0113] The concentration of each target in the standard working solution is used as the horizontal axis, and the corresponding response value of each target is used as the vertical axis. The standard working curves of 26 targets are fitted. The working curves are forced to pass through the origin to obtain the linear regression equation and correlation coefficient. The linear correlation coefficient of each target is r >0.999, which proves that it has a good linear relationship in the range of 0.006~6μg / mL. Figure 1 The liquid chromatograms of the 26 aldehydes and ketones obtained (concentration 0.6 μg / mL) are shown in Table 1. The retention times, linear equations and linear correlation coefficients of the 26 aldehydes and ketones are shown in Table 1.

[0114]

[0115] Example 2 Take 10 μL of a mixed standard working solution of 26 aldehydes and ketones-DNPH derivatives with a concentration of 3 μg / mL and add it to the DNPH sampling tube from the sampling port to simulate the sampling state. Use a calibrated sampling pump to collect 60 L of air at a flow rate of 1 L / min. Seal the sampling tube and place it in an aluminum foil bag. After placing it in the specified environment for 2 hours, elute it with acetonitrile. The environmental parameters for the simulated sampling and placement process are: in a constant temperature and humidity clean chamber with a temperature of (23±2)°C, a relative humidity of (50±5)%, and a background hydrocarbon concentration of <1ppm. The elution process is as follows: Use a disposable syringe to draw up a certain amount of acetonitrile and elute in the opposite direction of the sampling direction, controlling the elution rate at 2-3 mL / min. Collect the eluate in a 5 mL volumetric flask and adjust the volume to 5 mL. Finally, transfer it into a 2 mL injection vial for HPLC analysis.

[0116] According to the above test steps, the theoretical concentration value of the sample solution obtained is the concentration value of the linear lowest concentration point of 0.006 μg / mL.

[0117] Ten replicates were tested repeatedly and analyzed according to the liquid chromatography conditions in Example 1. The detection limits (LOD μg / mL) of the 26 target substances were calculated based on the target concentrations corresponding to three times the standard deviation of the replicate results. The detection limits were low and the sensitivity was good. When the gas sampling volume was 60 L and the elution volume was 5 mL of acetonitrile solution, the corresponding method detection limits (LOD μg / mL) were calculated. 3 ), considering the actual test situation, the linear concentration low point of the standard working solution was selected as 0.006 μg / mL to convert the concentration of each target substance to 0.5 μg / mL 3 As the method limit of quantification (LOQ μg / m 3 The detection limits and quantification limits of the methods corresponding to each target compound are shown in Table 2.

[0118]

[0119] Example 3 The principle of HPLC determination of aldehydes and ketones is to detect the corresponding hydrazone derivatives of aldehydes and ketones using a UV detector or diode array detector (DAD) at a specific absorption wavelength. This method has high selectivity. To eliminate the possibility of matrix interference, blank and spiked blank tests were performed using the HPLC conditions described in Example 1, using the theoretical concentration of 0.6 μg / mL, the midpoint of a mixed standard working solution of 26 aldehydes and ketones-DNPH derivatives, to assess the specificity of the method.

[0120] For a blank spike recovery test, a specific volume of standard working solution (80 μL of a standard mixture of 25 aldehyde-ketone-DNPH derivatives (15 mg / L dissolved in acetonitrile) and 44.32 μL of a cyclopentanone-DNPH (Grade II) standard stock solution) was added to a DNPH sampling tube to simulate sampling conditions. A calibrated sampling pump was used to sample 60 L of air at a flow rate of 1 L / min. The sampling tube was sealed and placed in an aluminum foil bag. After 2 hours of exposure to a specified temperature (23 ± 2°C, relative humidity (50 ± 5%)), the sample was eluted with acetonitrile (the elution procedure was the same as in Example 2, except that the eluate was collected in a 2 mL volumetric flask and the final volume was 2 mL). The sample was then analyzed by HPLC. A blank sample was run in parallel using the same testing procedure as the spiked sample, except that the standard working solution was omitted.

[0121] The chromatograms of blank solution and blank spiked solution are shown in the attached diagrams. Figure 2 and attached Figure 3 As shown in the attached Figures 1-3 It can be seen that there are no interfering substances in the blank sample, and no interfering substances in the blank spiked sample overlap with the chromatographic peaks of the target compound, which meets the method specificity requirements.

[0122] Example 4 The precision and accuracy of the method were investigated using the theoretical value of the intermediate concentration standard working solution of 0.6 μg / mL: 80 μL of a 15 μg / mL stock solution of a standard mixture of 25 aldehyde-ketone-DNPH derivatives and 44.32 μL of a cyclopentanone-DNPH (Grade II) standard stock solution were added to a DNPH sampling tube from the sampling port to simulate sampling conditions. Using a calibrated sampling pump, 60 L of air was collected at a flow rate of 1 L / min. The sampling tube was sealed and placed in an aluminum foil bag. After standing for 2 hours under the specified conditions, the air was eluted with acetonitrile (the elution process was the same as in Example 2, but the eluent was collected in a 2 mL volumetric flask and the final volume was adjusted to 2 mL). The simulated sampling and holding conditions were performed in a constant temperature and humidity cleanroom at (23 ± 2)°C, a relative humidity of (50 ± 5)%, and a background hydrocarbon concentration of <1 ppm.

[0123] Six replicates were tested using the above method and analyzed using the liquid chromatography conditions described in Example 1. The relative standard deviations (RSDs) for the 26 target compounds ranged from 0.09% to 1.68%, demonstrating good method precision. The recoveries and relative errors for the 26 target compounds were calculated, and the relative errors were <10%, meeting the trueness requirement. Overall evaluation confirmed that the method's accuracy met analytical requirements. The relative standard deviations, recoveries, and relative errors for the 26 aldehydes and ketones are shown in Table 3.

[0124]

[0125] Example 5 Take 1m sample of composite flat material for automotive interior 2 Before testing, remove the outer packaging of the sample and place it in a constant temperature and humidity room with a temperature of (23±2)℃ and a relative humidity of (50±5)% for 7 days before starting the test.

[0126] After aging in a 1 cubic meter test chamber, the background total hydrocarbon concentration in the chamber was continuously monitored using an online FID (needed to be less than 1.0 ppm). The test chamber equilibrium treatment conditions were set as follows: temperature 65°C, relative humidity 5%, and gas exchange rate 0.4h -1 After all parameters are stable, background blank tubes are collected. Background blank samples of 26 aldehyde and ketone compounds are collected using DNPH sampling tubes. The sampling parameters are: 1L / min, and 60L of cabin gas is collected.

[0127] After the blank sample is collected, place the sample in the cabin, quickly close the cabin door, and start the test.

[0128] The sample sampling time is 3 hours after the sample is placed in the chamber. The sample gas is collected using a DNPH sampling tube. The sampling parameter is: 1L / min, and 60L of chamber gas is collected.

[0129] The sample tubes and blank tubes after sampling were eluted according to the elution process in Example 2 to obtain sample solutions and blank solutions. Mixed standard working solutions of 26 aldehyde and ketone-DNPH derivatives at concentrations of 0.006 μg / mL, 0.06 μg / mL, 0.3 μg / mL, 0.6 μg / mL, 1.5 μg / mL, 3 μg / mL, and 6 μg / mL were taken and analyzed together with the eluted sample solutions and blank solutions using the liquid chromatography conditions in Example 1.

[0130] Using the standard working solution, the concentration of each target analyte is used as the horizontal axis and the corresponding response value is used as the vertical axis to draw the standard working curve of 26 aldehyde and ketone compounds. The standard working curve is forced to pass through the origin, and the correlation coefficient is r >0.999.

[0131] After subtracting the corresponding blank peak area from the peak area of ​​each target in the sample obtained by instrument analysis, the corresponding content (μg / mL) is calculated according to the standard working curve of each target. Then, the content of each target in the actual sample is calculated according to the following formula:

[0132] Where: G ——Volatilization amount of the sample to be tested, unit: μg / m 3 ; W——The amount of compound captured in the sample tube after deducting the background blank, calculated by the regression equation of the standard curve, unit: μg / mL; e ——Constant volume of acetonitrile eluent, mL; Q ——Convert the amount of gas collected in the sample tube according to 23℃ and 101.3KPa. The unit is L. The specific conversion formula is as follows:

[0133] in: V ——Actual sampling volume, unit: L; T ——Absolute temperature of the sampling point during sampling, unit: K; T x — absolute temperature at the reference state, 296.15 K; P ——The atmospheric pressure at the sampling point during sampling, unit: kPa; P x ——Atmospheric pressure under reference conditions, 101.3 kPa.

[0134] The sample analysis results are shown in Table 4.

[0135]

[0136] Note: ND means not detected.

[0137] Example 6 Take a front seat assembly from an automobile interior. Remove the sample's outer packaging before testing. Precondition it in a constant temperature and humidity room at (23±2)°C and (50±5)% for 24 hours before testing.

[0138] The size of the sampling bag is 2000 L.

[0139] Place the sample into an aged sampling bag, seal the bag with sealing strips, and evacuate the bag using a diaphragm vacuum pump to check for leaks. After leak testing, replace the bag with high-purity nitrogen: fill it to 50% of its volume, shake well, and then remove the nitrogen. Repeat this process twice. After replacement, fill the bag with nitrogen to an accurate 50% of its volume. Move the bag to a constant temperature chamber and equilibrate at 60°C for 2 hours. Then, use a DNPH sampling tube to collect samples of aldehydes and ketones at a sampling rate of 1 L / min, collecting 60 L of bag gas.

[0140] The background blank bag was tested in parallel with the sample, and the preparation process, sampling process and parameters were the same as those of the sample, except that no sample was placed in it.

[0141] The elution, instrument analysis and result calculation procedures of the sample tube and blank tube are the same as those in Example 5.

[0142] The sample analysis results are shown in Table 5.

[0143]

[0144] Note: ND means not detected, and “<0.5” means detected but below the limit of quantification.

[0145] Example 7 The whole vehicle is used as the test sample. Before the test, the sampling environment of the whole vehicle VOC environmental chamber is adjusted to: Temperature: 23.0℃; Relative humidity: 50%.

[0146] Vehicle preparation phase: Place the vehicle under test in the whole-vehicle VOC sampling chamber, remove any coverings from the internal components, and move them outside the sampling chamber. Fully open all windows and doors of the vehicle under test, and allow it to sit for 6 hours.

[0147] During the final hour of the preparatory phase, use a DNPH sampling tube to collect a blank sample from the environmental chamber. The sampling point is 0.5 meters from the vehicle body, at a height consistent with the driver and passenger breathing zone (1.2 to 1.5 meters). Collect one DNPH tube as the environmental blank (to measure the environmental background value before the test, which is not included in the final result calculation).

[0148] Vehicle closure phase: Use a bracket to arrange the sampling pipeline, and arrange one sampling point in the car, which is located at the intersection of the line connecting the front seat headrests and the center axis of the car.

[0149] The sampling point entrance should be at the same height as the driver's breathing zone (1.2 to 1.5 meters). The exit should be sealed with a plug to prevent leakage of gas from the vehicle. The sampling tube should be led out from the vehicle door without compromising the integrity and sealing of the vehicle.

[0150] Completely close all windows and doors of the vehicle under inspection, and let it stand for 16 hours while balancing.

[0151] Sample collection phase: Connect the sample tube to the outlet end of the sampling catheter and collect two DNPH tubes; record the conditions of the inspected vehicle, sampling date, time, location, atmospheric pressure, temperature, relative humidity, airflow velocity, etc.; sample the background blank sample at the same time, the sampling point is 0.5m from the vehicle body, the height is consistent with the breathing zone height of the driver and passengers (1.2m~1.5m), and collect one DNPH tube.

[0152] The sampling parameters of the DNPH blank tube and sample tube are: sampling flow rate is 1L / min, and 60L of gas is collected.

[0153] The elution, instrument analysis and result calculation procedures of the sample tube and blank tube are the same as those in Example 5.

[0154] The sample analysis results are shown in Table 6.

[0155]

[0156] Note: ND means not detected, and “<0.5” means detected but below the limit of quantification.

[0157] Example 8 The detection method of the present invention can be applied to the fields of ambient air and indoor air quality detection, and the application of the analysis method of the present invention to the detection of aldehyde and ketone compounds in indoor air is taken as an example.

[0158] The sampling method refers to the GB / T 18883-2022 indoor air quality standard, and the organic pretreatment room of the chemical laboratory is used as the sampling object.

[0159] Before sampling, close doors, windows, air purification equipment, and fresh air systems for 12 hours. During sampling, doors, windows, air purification equipment, and fresh air systems should remain closed.

[0160] Single-point sampling is performed at the center of the house, away from ventilation holes, at a distance greater than 0.5m from the wall, and greater than 1m from doors and windows. The height of the sampling point is consistent with the height of the human breathing zone, and the sampling point height is 1.4m.

[0161] Complete the point layout according to the previous steps, connect the sampling tube to the sampling pump, adjust the appropriate sampling flow rate and complete the calibration of the sampling equipment before starting to collect air samples.

[0162] The sampling parameters of the DNPH sample tube are: sampling flow rate is 1L / min, and 60L of gas is collected.

[0163] The elution and instrument analysis procedures of the sample tube are the same as those in Example 5.

[0164] Then calculate the content of each target object in the air of the sampling object according to the following formula:

[0165] Where: G’ ——Concentration of each target in the air, unit: μg / m 3 ; W’——The content of the compound captured by the sample tube calculated by the regression equation of the standard curve, unit: μg / mL; e ——Constant volume of acetonitrile eluent, mL; Q ——Convert the amount of gas collected in the sample tube according to 23°C and 101.3 KPa. The unit is L. The specific conversion formula is as follows:

[0166] in: V ——Actual sampling volume, unit: L; T ——Absolute temperature of the sampling point during sampling, unit: K; T x — absolute temperature at the reference state, 296.15 K; P ——The atmospheric pressure at the sampling point during sampling, unit: kPa; P x ——Atmospheric pressure under reference conditions, 101.3 kPa.

[0167] The sample analysis results are shown in Table 7.

[0168]

[0169] Note: ND means not detected.

[0170] Example 9 This example is a verification example of the liquid chromatograph analysis parameters, which are as follows: Liquid chromatography conditions: Chromatographic column: First chromatographic column: CNW Athena type (C18, 4.6 mm×250 mm, 5 µm), Secondary chromatographic column: GL Sciences ODS-P (C18, 4.6 mm × 250 mm, 5 µm), The chromatographic columns are connected in sequence; Mobile phase: Phase A is water, phase B is acetonitrile; Injection volume: 12 μL; Flow rate: 1.0 mL / min; Column temperature: 40°C; Diode array detector, detection wavelength is 367nm; The gradient elution program is as follows:

[0171] Take 0.6 μg / mL of the mixed standard working solution of 26 aldehydes and ketones-DNPH derivatives and analyze it according to the above analysis parameters. The obtained chromatogram is shown in the attached figure. Figure 4 As shown. Figure 4 It can be seen that the analysis method in this embodiment can meet the requirements of complete and effective separation and accurate quantification of 26 aldehyde and ketone compounds at the same time, and its technical effect is basically equivalent to that obtained by the analysis method in Example 1.

[0172] Example 10 This example is a verification example of the liquid chromatograph analysis parameters, which are as follows: Liquid chromatography conditions: Chromatographic column: First chromatographic column: CNW Athena type (C18, 4.6 mm×250 mm, 5 µm), Secondary chromatographic column: GL Sciences ODS-P (C18, 4.6 mm × 250 mm, 5 µm), The chromatographic columns are connected in sequence; Mobile phase: Phase A is water, phase B is acetonitrile; Injection volume: 12 μL; Flow rate: 1.0 mL / min; Column temperature: 40°C; Diode array detector, detection wavelength is 367nm; The gradient elution program is as follows:

[0173] Take 0.6 μg / mL of the mixed standard working solution of 26 aldehydes and ketones-DNPH derivatives and analyze it according to the above analysis parameters. The obtained chromatogram is shown in the attached figure. Figure 5 As shown. Figure 5 It can be seen that the analytical method in the present embodiment can meet the simultaneous effective separation and accurate quantification of 26 kinds of aldehydes and ketones. Compared with the analytical method in Example 1, the separation of glutaraldehyde 14 and cyclohexanone 15 is poor, but it can still meet the needs of analysis. Therefore, the analytical parameters in this analytical method are a critical parameter for achieving the simultaneous effective separation of 26 kinds of aldehydes and ketones.

[0174] Example 11 This example is a verification example of the liquid chromatograph analysis parameters, which are as follows: Liquid chromatography conditions: Chromatographic column: First chromatographic column: CNW Athena type (C18, 4.6 mm×250 mm, 5 µm), Secondary chromatographic column: GL Sciences ODS-P (C18, 4.6 mm × 250 mm, 5 µm), The chromatographic columns are connected in sequence; Mobile phase: Phase A is water, phase B is acetonitrile; Injection volume: 12 μL; Flow rate: 1.0 mL / min; Column temperature: 40°C; Diode array detector, detection wavelength 367 nm; The gradient elution program is as follows:

[0175] Take 0.6 μg / mL of the mixed standard working solution of 26 aldehydes and ketones-DNPH derivatives and analyze it according to the above analysis parameters. The obtained chromatogram is shown in the attached figure. Figure 6 As shown. Figure 6 It can be seen that the analytical method in this example can achieve the complete and effective separation and accurate quantification of 26 aldehyde and ketone compounds, achieving the technical effect to be achieved by the present invention. Compared with the analytical method in Example 1, 2-butanone 9 and n-butyraldehyde 10 can be effectively separated, but their chromatographic peaks gradually approach each other, demonstrating that subtle changes in the gradient elution procedure have a certain impact on the resolution of difficult-to-separate components.

[0176] Example 12 This example is a verification example of the liquid chromatograph analysis parameters, which are as follows: Liquid chromatography conditions: Chromatographic column: First chromatographic column: CNW Athena type (C18, 4.6 mm×250 mm, 5 µm), Secondary chromatographic column: GL Sciences ODS-P (C18, 4.6 mm × 250 mm, 5 µm), The chromatographic columns are connected in sequence; Mobile phase: Phase A is water, phase B is acetonitrile; Injection volume: 12 μL; Flow rate: 1.0 mL / min; Column temperature: 35°C; Diode array detector, detection wavelength 367 nm; The gradient elution program is as follows:

[0177] Take 0.6 μg / mL of the mixed standard working solution of 26 aldehydes and ketones-DNPH derivatives and analyze it according to the above analysis parameters. The obtained chromatogram is shown in the attached figure. Figure 7 As shown. Figure 7 It can be seen that the analysis method in this embodiment can meet the requirements of complete and effective separation and accurate quantification of 26 aldehyde and ketone compounds at the same time, and its technical effect is basically equivalent to that obtained by the analysis method in Example 1.

[0178] Example 13 This example is a verification example of the liquid chromatograph analysis parameters, which are as follows: Liquid chromatography conditions: Chromatographic column: First chromatographic column: CNW Athena type (C18, 4.6 mm × 250 mm, 5 µm), Secondary chromatographic column: GL Sciences ODS-P (C18, 4.6 mm × 250 mm, 5 µm), The chromatographic columns are connected in sequence; Mobile phase: Phase A is water, phase B is acetonitrile; Injection volume: 12 μL; Flow rate: 1.0 mL / min; Column temperature: 32°C; Diode array detector, detection wavelength is 367nm; The gradient elution program is as follows:

[0179] Take 0.6 μg / mL of the mixed standard working solution of 26 aldehydes and ketones-DNPH derivatives and analyze it according to the above analysis parameters. The obtained chromatogram is shown in the attached figure. Figure 8 As shown. Figure 8 It can be seen that the analysis method in this embodiment can meet the requirements of complete and effective separation and accurate quantification of 26 aldehyde and ketone compounds at the same time, and its technical effect is basically equivalent to that obtained by the analysis method in Example 1.

[0180] Example 14 This example is a verification example of the liquid chromatograph analysis parameters, which are as follows: Liquid chromatography conditions: Chromatographic column: First chromatographic column: CNW Athena type (C18, 4.6 mm × 250 mm, 5 µm), Secondary chromatographic column: GL Sciences ODS-P (C18, 4.6 mm × 250 mm, 5 µm), The chromatographic columns are connected in sequence; Mobile phase: Phase A is water, phase B is acetonitrile; Injection volume: 12 μL; Flow rate: 1.0 mL / min; Column temperature: 30°C; Diode array detector, detection wavelength is 367nm; The gradient elution program is as follows:

[0181] Take 0.6 μg / mL of the mixed standard working solution of 26 aldehydes and ketones-DNPH derivatives and analyze it according to the above analysis parameters. The obtained chromatogram is shown in the attached figure. Figure 9 As shown. Figure 9 It can be seen that the analytical method in this embodiment can achieve complete and effective separation and accurate quantification of 26 aldehyde and ketone compounds. Compared with the analytical method in Example 1, the chromatographic peaks of cyclohexanone 15 and valeraldehyde 16 gradually approach each other, but this has no effect on the separation effect. Overall, the technical results obtained by the analytical method in this embodiment are basically equivalent to those obtained by the analytical method in Example 1.

[0182] Comparative Example 1 In order to further prove that the technical effect of the method provided by the present invention is superior to the existing technology, a comparative test is now carried out.

[0183] The chromatographic column is a key factor in achieving the technical effects of the present invention. The CNW Athena (C18, 4.6 mm × 250 mm, 5 µm) chromatographic column is a commercially available HPLC column suitable for separating non-polar, polar, or ionic compounds. It is also the chromatographic column used in the closest prior art (Chinese invention patent application, application number 202411163439.6). Therefore, using this chromatographic column, the analytical parameters used in the present invention (excluding the chromatographic column system), the analytical parameters in the Chinese invention patent application (application number 202411163439.6) (a ternary mobile phase system of water-acetonitrile-tetrahydrofuran), and a binary mobile phase system of water-acetonitrile with a rapid gradient elution procedure were employed to investigate the separation ability of the CNW Athena column for 26 aldehydes and ketones. The specific experimental conditions are as follows: Scheme 1. Analyze using the same analytical conditions as the present invention: Liquid chromatography conditions: Chromatographic column: CNW Athena type (C18, 4.6 mm × 250 mm, 5 µm); Mobile phase: Phase A is water, phase B is acetonitrile; Injection volume: 12 μL; Flow rate: 1.0 mL / min; Column temperature: 40°C; Diode array detector, detection wavelength is 367nm; The gradient elution program is as follows:

[0184] Scheme 2. Analysis using a water-acetonitrile-tetrahydrofuran ternary mobile phase system: The analysis parameters adopted those in the Chinese invention patent application (application number 202411163439.6, invention title: A method for detecting 25 aldehydes and ketones in automotive interior materials and components).

[0185] Liquid chromatography conditions: Chromatographic column: CNW Athena type (C18, 4.6 mm × 250 mm, 5 µm); Mobile phase: Phase A is water, phase B is acetonitrile, and phase D is tetrahydrofuran; Injection volume: 20 μL; Flow rate: 1.0 mL / min; Column temperature: 40°C; Diode array detector, detection wavelength is 367nm; The gradient elution program is as follows:

[0186] Option 3. Analysis using a water-acetonitrile binary mobile phase system: A water-acetonitrile binary mobile phase system was used with a rapid detection gradient elution procedure for analysis.

[0187] Liquid chromatography conditions: Chromatographic column: CNW Athena type (C18, 4.6 mm × 250 mm, 5 µm); Mobile phase: Phase A is water, phase B is acetonitrile; Injection volume: 12 μL; Flow rate: 1.2 mL / min; Column temperature: 40°C; Diode array detector, detection wavelength is 367nm; The gradient elution program is as follows:

[0188] Take 0.6 μg / mL of mixed standard working solution of 26 aldehydes and ketones-DNPH derivatives and analyze them according to the above analysis schemes 1 to 3. The chromatograms obtained are as shown in the attached figure. Figures 10-12 shown.

[0189] From the attached Figure 10 It can be seen that using a CNW Athena type (C18, 4.6 mm×250 mm, 5 µm) chromatographic column, Scheme 1 combined with the mobile phase system and gradient elution parameters of the present invention, it is impossible to achieve effective separation of 26 aldehydes and ketones simultaneously. Among them, furanaldehyde 3 and acrolein 4, n-butyraldehyde 10 and cyclopentanone 11 coeluted and could not be separated, and m-methylbenzaldehyde 18 and p-methylbenzaldehyde 19 could only be slightly separated at the top peak and approached coelution. These groups of substances are all compounds that are difficult to separate simultaneously in the analysis of aldehydes and ketones.

[0190] Scheme 2 uses the closest analytical method in the prior art, using a water-acetonitrile-tetrahydrofuran ternary mobile phase system, but it is also unable to complete the simultaneous separation of 26 aldehydes and ketones. Figure 11 It can be seen that 2-butanone 9 and cyclopentanone 11, m-tolualdehyde 18 and p-tolualdehyde 19 coelute and cannot be separated.

[0191] Scheme 3 uses a rapid analysis method, using a water-acetonitrile binary mixed system with corresponding gradient elution parameters, but it is also unable to complete the simultaneous separation of 26 aldehydes and ketones. Figure 12 It can be seen that furanaldehyde 3 and acrolein 4, n-butyraldehyde 10 and cyclopentanone 11 co-elute and cannot be separated, m-tolualdehyde 18 and p-tolualdehyde 19 can only be slightly separated at the top peak and are close to co-elution. The co-elution combination is the same as the co-elution combination in Scheme 1.

[0192] Therefore, it can be inferred that the use of a CNW Athena type (C18, 4.6 mm × 250 mm, 5 µm) chromatographic column, regardless of whether it is combined with a ternary mobile phase system or a binary mobile phase system, or the same mobile phase system with different gradient elution procedures, cannot achieve the technical effect of simultaneous effective separation and accurate quantification of 26 aldehydes and ketones.

[0193] Comparative Example 2 In order to further prove that the technical effect of the method provided by the present invention is superior to the existing technology, a comparative test is now carried out.

[0194] The GL Sciences ODS-P (C18, 4.6 mm × 250 mm, 5 µm) column is also a commercially available HPLC column suitable for separating non-polar, polar, or ionic compounds. This column is also used in this invention. Therefore, using this column, the analytical parameters used in this invention (excluding the column system) and the analytical parameters described in the Chinese invention patent application (Application No. 202411163439.6) (a ternary mobile phase system of water-acetonitrile-tetrahydrofuran) and a binary mobile phase system of water-acetonitrile with a rapid gradient elution procedure were employed to investigate the separation ability of the GL Sciences ODS-P column for 26 aldehydes and ketones. The specific experimental conditions are as follows: Scheme 1. Analyze using the same analytical conditions as the present invention: Liquid chromatography conditions: Chromatographic column: GL Sciences ODS-P (C18, 4.6 mm × 250 mm, 5 µm); Mobile phase: Phase A is water, phase B is acetonitrile; Injection volume: 12 μL; Flow rate: 1.0 mL / min; Column temperature: 40°C; Diode array detector, detection wavelength is 367nm; The gradient elution program is as follows:

[0195] Scheme 2. Analysis using a water-acetonitrile-tetrahydrofuran ternary mobile phase system: The chromatographic column used was GL Sciences ODS-P, and the other analytical parameters used were those in the Chinese invention patent application (application number 202411163439.6, invention title: A method for detecting 25 aldehydes and ketones in automotive interior materials and components).

[0196] Liquid chromatography conditions: Chromatographic column: GL Sciences ODS-P (C18, 4.6 mm × 250 mm, 5 µm); Mobile phase: Phase A is water, phase B is acetonitrile, and phase D is tetrahydrofuran; Injection volume: 20 μL; Flow rate: 1.0 mL / min; Column temperature: 40°C; Diode array detector, detection wavelength is 367nm; The gradient elution program is as follows:

[0197] Scheme 3. Analysis using a water-acetonitrile binary mobile phase system: A water-acetonitrile binary mobile phase system was used with a rapid detection gradient elution procedure for analysis.

[0198] Liquid chromatography conditions: Chromatographic column: GL Sciences ODS-P (C18, 4.6 mm × 250 mm, 5 µm); Mobile phase: Phase A is water, phase B is acetonitrile; Injection volume: 12 μL; Flow rate: 1.2 mL / min; Column temperature: 40°C; Diode array detector, detection wavelength is 367nm; The gradient elution program is as follows:

[0199] Take 0.6 μg / mL of the mixed standard working solution of 26 aldehydes and ketones-DNPH derivatives and analyze them according to the above analysis schemes 1 to 3. The chromatograms obtained are as shown in the attached figure. Figures 13-15 shown.

[0200] From the attached Figure 13 It can be seen that using a GL Sciences ODS-P type (C18, 4.6 mm×250 mm, 5 µm) chromatographic column, Scheme 1 combined with the mobile phase system and gradient elution parameters of the present invention, it is impossible to achieve the simultaneous separation of 26 aldehyde and ketone compounds. Among them, 2-butanone 9 and n-butyraldehyde 10 coelute and cannot be separated. The chromatographic peaks of their coelution are poorly resolved from the chromatographic peak of cyclopentanone 11 and can only be slightly separated at the peak top. At the same time, the separation of 2,5-dimethylbenzaldehyde 22 and cyclohexanone 15 is also poor, and they can only be slightly separated at the peak top.

[0201] Scheme 2 uses the closest analytical method in the prior art, using a water-acetonitrile-tetrahydrofuran ternary mobile phase system, but it is also unable to complete the simultaneous separation of 26 aldehydes and ketones. Figure 14 As can be seen, furanaldehyde 3 and acrolein 4, 2-butanone 9 and cyclopentanone 11, glutaraldehyde 14 and o-methylbenzaldehyde 17, and hexanal 21 and 2,5-dimethylbenzaldehyde 22 coeluted and could not be separated. m-methylbenzaldehyde 18 and p-methylbenzaldehyde 19 could only be separated at the peak top, with poor resolution. Using the ODS-P column with the analytical parameters in this protocol, the results showed that a large number of groups of targets coeluted, demonstrating the influence of differences between chromatographic columns and their synergistic effect with the mobile phase system and gradient elution procedure on the resolution of the targets.

[0202] Scheme 3 uses a rapid analysis method, using a water-acetonitrile binary mixed system with corresponding gradient elution parameters, but it is also unable to complete the simultaneous separation of 26 aldehydes and ketones. Figure 15 It can be seen that 2-butanone 9 and n-butyraldehyde 10 co-elute and cannot be separated, and the separation degree of their co-eluted chromatographic peak is poor compared with the chromatographic peak of cyclopentanone 11, and they can only be slightly separated at the peak top; at the same time, the separation degree of 2,5-dimethylbenzaldehyde 22 and cyclohexanone 15 is poor, and they can only be slightly separated at the peak top. The combination of co-eluting substances and the combination of substances with poor separation degree in this scheme are the same as those in scheme 1.

[0203] Therefore, it can be inferred that the use of a GL Sciences ODS-P (C18, 4.6 mm×250 mm, 5 µm) chromatographic column, regardless of whether it is combined with a ternary mobile phase system or a binary mobile phase system, or the same mobile phase system with different gradient elution procedures, cannot achieve the technical effect of simultaneous effective separation and accurate quantification of 26 aldehydes and ketones.

[0204] As can be seen from Comparative Examples 1 and 2, there are differences in the performance of the two chromatographic columns used in the present invention. There are certain differences in the separation ability of 26 kinds of aldehydes and ketones using the same analytical parameters, and there are certain differences in the effluent time and order of some aldehydes and ketones. The several groups of substances that cannot be separated at the same time are all groups of compounds that are difficult to complete separation at the same time in aldehydes and ketones. It can be seen from this that when the two chromatographic columns used in the present invention are used alone, no matter whether they are combined with a ternary mobile phase system or a binary mobile phase system, or different gradient elution procedures of the same mobile phase system, the technical effect of the complete and effective separation of 26 kinds of aldehydes and ketones cannot be completed at the same time, thereby failing to complete the purpose of quantifying 26 kinds of aldehydes and ketones in 1 analysis.

[0205] Comparative Example 3 In order to further prove that the technical effect of the method provided by the present invention is superior to the existing technology, a comparative test is now carried out.

[0206] Based on the analysis of various types of aldehyde and ketone compounds by high performance liquid chromatography, the chromatographic column, elution system and supporting gradient elution program are the three most critical factors affecting the separation degree of the target, and the interaction and synergy between the three play a vital role in the final separation effect. The more types of target objects, the more combinations of difficult-to-separate compounds with similar properties involved, and the higher the requirements for analysis parameters. The various parameters in the analysis method need to cooperate with each other, and slight changes may lead to changes in the separation degree of the target, thereby affecting the realization of the technical effect of the invention method. Comparative Examples 1 and 2 respectively investigate the influence of the chromatographic column. This comparative example investigates the separation of 26 kinds of aldehyde and ketone compounds required to be separated by the present invention under the condition of using two columns in series. The specific experimental conditions are as follows: Scheme 1. Analysis using a water-acetonitrile-tetrahydrofuran ternary mobile phase system: The tandem chromatographic column system of the present invention was used, and the remaining analysis parameters were the parameters of the Chinese invention patent application (application number 202411163439.6, invention title: A method for detecting 25 aldehydes and ketones in automotive interior materials and components).

[0207] Liquid chromatography conditions: Chromatographic column: First chromatographic column: CNW Athena type (C18, 4.6 mm × 250 mm, 5 µm), Secondary chromatographic column: GL Sciences ODS-P (C18, 4.6 mm × 250 mm, 5 µm), The chromatographic columns are connected in sequence; Mobile phase: Phase A is water, phase B is acetonitrile, and phase D is tetrahydrofuran; Injection volume: 20 μL; Flow rate: 1.0 mL / min; Column temperature: 40°C; Diode array detector, detection wavelength is 367nm; The gradient elution program is as follows:

[0208] Scheme 2. Analyze using a water-acetonitrile binary mobile phase system and its accompanying gradient elution procedure reported in existing literature: Method A: Li Lirong et al. developed a method for analyzing 25 aldehyde and ketone carbonyl compounds in air (paper titled "Determination of 25 Aldehydes and Ketones in Air by Liquid Chromatography and Liquid Chromatography-Mass Spectrometry"). While the targets analyzed overlap significantly with those of the present invention, their HPLC method failed to separate cyclohexanone and glutaraldehyde due to coelution, and para-, meta-tolualdehyde could only be separated at the peak apex. We now employ a dual-column tandem system, combining the mobile phase system and accompanying gradient elution procedure of their HPLC method, along with all analytical parameters other than the chromatographic column, to conduct a comparative analysis of the 26 aldehyde and ketone compounds described in the present invention. The specific analytical conditions are as follows.

[0209] Liquid chromatography conditions: Chromatographic column: First chromatographic column: CNW Athena type (C18, 4.6 mm × 250 mm, 5 µm), Secondary chromatographic column: GL Sciences ODS-P (C18, 4.6 mm × 250 mm, 5 µm), The chromatographic columns are connected in sequence; Mobile phase: Phase A is water, phase B is acetonitrile; Injection volume: 10 μL; Flow rate: 1.0 mL / min; Column temperature: 40°C; Diode array detector, detection wavelength is 367nm; The gradient elution program is as follows:

[0210] Method B: Wang Wei et al. developed a method for the simultaneous determination of 25 aldehydes and ketones in wood products (paper title: "Simultaneous Determination of 25 Aldehydes and Ketones in Wood Products by DNPH Derivatization Sampling-Solvent Desorption-High-Performance Liquid Chromatography"). The spectra show that 2-butanone and n-butyraldehyde, cyclohexanone, and valeraldehyde cannot be effectively separated. The 25 aldehydes and ketones identified in this method differ slightly from the target aldehydes and ketones described in the present invention, but they largely overlap. Therefore, the analytical parameters of this method were employed to attempt to analyze the 26 aldehydes and ketones required for separation in the present invention. A comparative analysis of the 26 aldehydes and ketones described in the present invention was conducted using a dual-column tandem system, combined with the developed mobile phase system and accompanying gradient elution procedure, and all analytical parameters other than the chromatographic columns. The specific analytical conditions are as follows.

[0211] Liquid chromatography conditions: Chromatographic column: First chromatographic column: CNW Athena type (C18, 4.6 mm × 250 mm, 5 µm), Secondary chromatographic column: GL Sciences ODS-P (C18, 4.6 mm × 250 mm, 5 µm), The chromatographic columns are connected in sequence; Mobile phase: Phase A is water, phase B is acetonitrile; Injection volume: 20 μL; Flow rate: 1.0 mL / min; Column temperature: 30°C; Diode array detector, detection wavelength is 367nm; The gradient elution program is as follows:

[0212] Take 0.6 μg / mL of the mixed standard working solution of 26 aldehydes and ketones-DNPH derivatives and analyze them according to the above analysis schemes 1 and 2. The chromatograms obtained are as shown in the attached figure. Figures 16-19 shown.

[0213] The patent document cited in Scheme 1 is in the same technical field as the present invention, and the technical problem to be solved is the closest. It has disclosed the most technical features and is the closest prior art. The use of two columns in series and the combination of the other analytical parameters disclosed in the patent document were used to analyze 26 aldehyde and ketone compounds. Figures 16 and 17 From the attached Figure 16 and attached Figure 17 It can be seen that this method cannot achieve the technical goal of completely and effectively separating 26 aldehyde and ketone compounds at the same time. Among them, furfural 3 and acrolein 4, methacrolein 8 and 2-butanone 9 are co-eluted and cannot be separated. Hexanal 21 and 2,5-dimethylbenzaldehyde 22 can only be separated at the peak with poor separation. The separation of glutaraldehyde 14 and valeraldehyde 16 is also poor. At the same time, due to the influence of the water-acetonitrile-tetrahydrofuran ternary mobile phase system on the solute elution ability, the peak time of each target is later than that of the water-acetonitrile binary mobile phase system, resulting in octanal 24, nonanal 25 and decanal 26 not eluting within the method acquisition time, and the signals of the corresponding substances were not collected. The attached Figure 16 and attached Figure 17 , compared with the attached product obtained in the second scheme in comparative example 1 Figure 11As can be seen, using the same mobile phase system and gradient elution program, and with all other parameters except the column being identical, substances that can be completely separated using a single CNW Athena column (such as furanaldehyde 3 and acrolein 4, and methacrolein 8 and 2-butanone 9) merge and coelute in a dual-column tandem system. This demonstrates that while a dual-column tandem system is beneficial for improving target resolution, the different properties of the tandem columns may cause the merged coelution of separated substances, and the separation effect may not necessarily be superior to that achieved using a single column. Therefore, when developing analytical methods for multiple aldehyde and ketone compounds, simply connecting chromatographic columns in series is not enough to improve target resolution. Comprehensive validation testing is still required for the selection of tandem columns, the selection of mobile phase systems, and the development of gradient elution programs.

[0214] The two methods in Scheme 2 both used the same water-acetonitrile binary mobile phase system as the present invention. To investigate the effect of the gradient elution procedure on the separation degree when the other analytical parameters remain unchanged, the analytical parameters reported by them were respectively used in combination with the dual-column series system of the present invention to comparatively analyze 26 target aldehyde and ketone compounds. Figure 18 (Method A) It can be seen that the analytical method parameters cannot achieve complete and effective separation of 26 aldehyde and ketone compounds at the same time. Among them, 2-butanone 9 and n-butyraldehyde 10 can only be slightly separated at the top peak and are close to co-eluting. Cyclohexanone 15 and valeraldehyde 16 coelute and cannot be separated. Figure 19 (Method B) It can be seen that the analytical method parameters cannot achieve complete and effective separation of 26 aldehyde and ketone compounds at the same time. Among them, 2-butanone 9 and n-butyraldehyde 10, cyclohexanone 15 and valeraldehyde 16 co-eluted and could not be separated. In addition, nonanal 25 and decanal 26 did not elute within the method acquisition time, and the signals of the corresponding substances were not collected.

[0215] The two liquid chromatography methods in the prior art cited in Scheme 2 have certain defects when separating their respective 25 target compounds, and are unable to effectively separate their corresponding target aldehyde and ketone compounds at the same time; and after using a series of columns combined with the corresponding other analytical parameters to compare and analyze the 26 aldehyde and ketone compounds, there is also the problem that multiple groups of difficult-to-separate compound combinations cannot be separated simultaneously. This also reflects from another perspective that simply connecting chromatographic columns in series to increase the column length cannot solve the problem of target separation, and multi-faceted collaborative development of various analytical parameters is still needed.

[0216] A comparison of the two methods in Scheme 2, A / B, demonstrates that even with the same dual-column system, identical mobile phase elution system, and similar gradient elution parameters, significant differences in analytical results (retention times, resolution, etc.) were observed, preventing the complete and effective separation of all 26 aldehyde and ketone compounds. In HPLC analysis, various analytical parameters interact with and influence each other. Achieving complete separation of multiple target compounds with similar properties requires the coordinated development of three key technical parameters: the chromatographic column, mobile phase system, and gradient elution procedure. These parameters, along with other parameters such as flow rate and column temperature, must be coordinated to achieve the desired technical objectives. Even subtle differences can lead to discrepancies in results, impacting the ultimate technical performance of the analytical method. Appropriate analytical parameters are determined through extensive experimental validation and cannot be achieved through transfer or simple transformation. Parameter development must also consider practical application factors such as method stability and reproducibility, as well as analytical efficiency and cost, to ultimately determine the most appropriate analytical parameters to achieve the desired technical results.

[0217] In the above two schemes, the substances that cannot be separated at the same time are all combinations of substances that are difficult to separate at the same time among the 26 kinds of aldehyde and ketone compounds, which further illustrates the influence of the combination of parameters of the chromatographic column, mobile phase system and gradient elution program on the separation degree of the 26 kinds of aldehyde and ketone compounds. It can be inferred from the experiments in this comparative example that even if the dual-column series system in the present invention is adopted, without the coordinated cooperation of a suitable mobile phase system and a supporting gradient elution program, the technical purpose of completely and effectively separating and accurately quantifying the 26 kinds of aldehyde and ketone compounds at the same time cannot be achieved.

[0218] It should be understood that the application of the present invention is not limited to the above examples. For those skilled in the art, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A method for detecting aldehyde and ketone compounds in the air, characterized in that: The following steps are involved: S1. Provide the sample to be tested and place it for later use after pretreatment; S2. Before starting the test, collect a background blank sample or collect a blank sample simultaneously with the sample. Use a sampling tube coated with 2,4-dinitrophenylhydrazine to collect a blank sample of aldehydes and ketones to obtain a blank tube; S3. The pre-treated sample to be tested is placed after equilibrium treatment and then the sample gas of aldehyde and ketone compounds is collected using a sampling tube coated with 2,4-dinitrophenylhydrazine to obtain a sample tube; S4. Elute the blank tube and sample tube with acetonitrile, and then adjust the volume to obtain blank solution and sample solution; S5. Prepare mixed standard working solutions of 26 aldehyde-ketone-DNPH derivatives at different concentrations and analyze them using high-performance liquid chromatography (HPLC) supplemented with a diode array detector (DAD). Plot standard working curves and obtain regression equations corresponding to each target compound. The aldehyde and ketone compounds are the following 26 kinds: Formaldehyde, acetaldehyde, furfural, acrolein, acetone, propionaldehyde, crotonaldehyde, methacrolein, 2-butanone, n-butyraldehyde, cyclopentanone, benzaldehyde, isovaleraldehyde, glutaraldehyde, cyclohexanone, valeraldehyde, o-methylbenzaldehyde, m-methylbenzaldehyde, p-methylbenzaldehyde, 4-methyl-2-pentanone, hexanal, 2,5-dimethylbenzaldehyde, heptaldehyde, octanal, nonanal, decanal; S6. The blank solution and the sample solution were analyzed using a high performance liquid chromatograph and detected using a diode array detector to obtain the peak area corresponding to each target in the blank solution and the sample solution. The peak area corresponding to each target in the sample solution was subtracted from the peak area corresponding to each target in the blank solution and the peak area was substituted into the corresponding standard curve regression equation to obtain the actual content of the 26 aldehyde and ketone compounds in the sample tube after deducting the background blank. The content of the 26 aldehyde and ketone compounds in the sample to be tested was then converted using the formula; The analysis conditions of the HPLC analysis method are: Chromatographic column: First chromatographic column: CNW Athena C18 column, 4.6 mm × 250 mm, 5 µm, Secondary column: GL Sciences ODS-P C18 column, 4.6 mm × 250 mm, 5 µm, The first chromatographic column and the second chromatographic column are sequentially connected in series; Mobile phase: Phase A is water, phase B is acetonitrile; Injection volume: 12 μL; Flow rate: 1.0 mL / min; Column temperature: 30~40℃; Diode array detector, detection wavelength is 367nm; The gradient elution program is as follows: 0 min, the proportion of mobile phase A was 40%, and the proportion of mobile phase B was 60%; 25 min, the proportion of mobile phase A was 35%, and the proportion of mobile phase B was 65%; 30 min, the proportion of mobile phase A was 0%, and the proportion of mobile phase B was 100%; 40 min, the proportion of mobile phase A was 0%, and the proportion of mobile phase B was 100%; 45 min, the proportion of mobile phase A was 40%, and the proportion of mobile phase B was 60%.

2. The method for detecting aldehydes and ketones in air according to claim 1, wherein The pretreatment temperature is a constant temperature of 20-25° C., the relative humidity is a constant humidity of 40-60%, and the pretreatment time is 6 hours to 7 days.

3. The method for detecting aldehydes and ketones in air according to claim 1, wherein The balancing treatment adopts a 1 cubic meter test chamber sampling method, and the 1 cubic meter test chamber sampling method collects a background blank sample before starting the test; Alternatively, the balancing treatment adopts a sampling bag sampling method, wherein a blank bag is taken for parallel testing, and a blank sample is collected synchronously with the sample; Alternatively, the balancing process adopts a whole vehicle sampling method, and the whole vehicle sampling method collects blank samples synchronously with the samples.

4. The method for detecting aldehydes and ketones in air according to claim 3, wherein The equilibrium processing temperature of the 1 cubic meter test chamber sampling method and the sampling bag sampling method is 60℃~65℃, and the equilibrium processing temperature of the whole vehicle sampling method is 23.0℃~25.0℃.

5. The method for detecting aldehydes and ketones in air according to claim 1, wherein The elution and volume setting include the following steps: Acetonitrile was used to elute the blank tube and the sample tube respectively in the opposite direction of the sampling direction, the eluted eluate was collected in a volumetric flask, and the volume was fixed with acetonitrile to obtain a blank solution and a sample solution.

6. The method for detecting aldehydes and ketones in the air according to claim 5, wherein: The speed of eluting the blank tube and the sample tube with acetonitrile in the opposite direction of the sampling direction is 2-3 mL / min.

7. The method for detecting aldehydes and ketones in air according to claim 1, wherein The 26 aldehyde-ketone-DNPH derivative mixed standard working solutions are prepared from a cyclopentanone-DNPH standard stock solution and a mixed standard solution of 25 aldehyde-ketone-DNPH derivative compounds.

8. The method for detecting aldehydes and ketones in air according to claim 7, wherein: The cyclopentanone-DNPH standard stock solution comprises the following preparation steps: Prepare hydrochloric acid buffer solution; Weigh 2,4-dinitrophenylhydrazine into a volumetric flask, add acetonitrile and ultrasonically vibrate to dissolve; Add hydrochloric acid buffer solution to the above solution and mix well; Weigh cyclopentanone and add it to the above solution for derivatization reaction so that the molar ratio of 2,4-dinitrophenylhydrazine to cyclopentanone is greater than 2:

1. After adjusting the volume with acetonitrile, shake the reaction in a water bath at 25-45°C for 10-50 minutes.

9. The method for detecting aldehyde and ketone compounds in the air according to claim 8, wherein During the derivatization reaction for preparing the cyclopentanone-DNPH standard stock solution, the concentration of the hydrochloric acid buffer solution is 1-2 mol / L.

10. The method for detecting aldehyde and ketone compounds in the air according to claim 1, wherein The concentration of the mixed standard working solution of the 26 aldehydes and ketones-DNPH derivatives is 0.006 μg / mL to 6 μg / mL.

11. The method for detecting aldehyde and ketone compounds in the air according to claim 1, wherein The actual contents of the 26 aldehyde and ketone compounds in the sample tube after deducting the background blank were calculated according to the regression equation of the standard curve, and then the actual contents of the 26 aldehyde and ketone compounds in the sample to be tested were calculated according to the following formula: Where: G ——Volatilization amount of the sample to be tested, unit: μg / m 3 ; W ——The amount of compound captured in the sample tube after deducting the background blank, calculated by the regression equation of the standard curve, unit: μg / mL; e ——Constant volume of acetonitrile eluent, mL; Q ——Convert the amount of gas collected in the sample tube according to 23℃ and 101.3KPa. The unit is L. The specific conversion formula is as follows: Where: V ——Actual sampling volume, unit: L; T ——Absolute temperature of the sampling point during sampling, unit: K; T x — absolute temperature at the reference state, 296.15 K; P ——The atmospheric pressure at the sampling point during sampling, unit: kPa; P x ——Atmospheric pressure under reference conditions, 101.3 kPa.

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