A method for testing volatile organic compounds in synthetic resin raw materials

Abstract

This invention provides a method for testing volatile organic compounds (VOCs) in synthetic resin raw materials. The method includes: S1: mixing synthetic resin particles with a solid-phase extraction (SPE) trap and sealing the mixture, allowing the SPE trap to collect VOCs from the synthetic resin particles; S2: performing low-temperature extraction on the SPE trap obtained in S1 using an extraction solvent, followed by low-temperature centrifugation to obtain the supernatant; S3: analyzing the supernatant using gas chromatography-high-resolution mass spectrometry (GC-MS), and then resolving the obtained mass spectrum to obtain information on all VOC components and their content. The method provided by this invention can improve the comprehensiveness and accuracy of detection, while also simplifying operation and increasing efficiency.

Description

Technical Field

[0001] This invention relates to a method for testing volatile organic compounds in synthetic resin raw materials, belonging to the field of analytical chemistry technology. Background Technology

[0002] Synthetic resins are widely used in daily life. Taking polypropylene as an example, polypropylene fabrics, masks, and automotive parts are ubiquitous in people's lives. These consumer goods made from synthetic resin raw materials often cause concern due to their odor. Raw material and product manufacturers are highly concerned about the odor of their raw materials and whether it poses any health risks.

[0003] Current methods for detecting the odor of raw materials and finished products mainly involve "olfactory classification," where odor assessors score the raw materials according to specific procedures: Level 1 is "undetectable," with higher levels indicating stronger odors, and Level 6 being "unbearable." Raw materials with excessively high odor levels are classified as substandard or defective. PV3900-2000, "Volkswagen Corporation's Odor Testing Method for Interior Components," is a typical example of this method. Odor classification only determines the intensity of the odor, without analyzing its composition or the presence of toxic or harmful substances. This type of method is not conducive to materials researchers developing and researching low-odor raw materials and products.

[0004] Odor is produced by volatile organic compounds (VOCs) in raw materials. VOCs with odor and low threshold are key substances that trigger human olfactory responses.

[0005] The main methods for analyzing volatile organic compounds (VOCs) in raw materials using instrumental analysis include headspace gas chromatography (HSCGC), exemplified by ASTM D4526-2012, "Standard Implementation Procedure for the Determination of Volatile Organic Compounds in Polymers by Headspace Gas Chromatography." However, this method is limited by the small headspace volume and lack of gas enrichment and concentration capabilities. Therefore, VOCs with low concentrations but low odor thresholds in synthetic resin raw materials may be overlooked and undetectable. To improve headspace enrichment capabilities, commonly used techniques such as purge-and-trap, Tenax tube trapping, solid-phase extraction coated with adsorbent packing, and aldehyde and ketone compound sampling tube trapping are collectively known as gas pretreatment techniques. These techniques all exhibit specific selectivity. The approach of selecting the appropriate adsorbent packing based on the type of compound to be detected is typical of known compound detection, leading to sampling discrimination for unknown compounds.

[0006] Methods exemplified by HJ / T400-2007, "Sampling and Determination Methods for Volatile Organic Compounds and Aldehydes and Ketones in Vehicle Interiors," include: environmental chamber sampling, which uses Tenax collection tubes to collect volatile organic compounds released from the sample into an environmental chamber, followed by thermal desorption-gas chromatography-mass spectrometry to determine total volatile organic compounds (the general term for volatile compounds with retention times between n-hexane and n-hexadecane); and selective collection and derivatization of aldehydes and ketones from volatile organic compounds using sampling tubes coated with 2,4-dinitrophenylhydrazine silica gel, followed by determination and analysis of aldehydes and ketones using liquid chromatography-ultraviolet or diode array detectors; and detection of several specified target compounds. These methods target both the target compounds and TVOCs. In practice, the process of packaging and transporting synthetic resin raw materials from the production plant to the laboratory for odor analysis is lengthy. The raw materials have low volatile organic compound content, are easily dispersed, and are easily contaminated by ambient air and packaging materials. Therefore, non-discriminatory capture and enrichment of volatile organic compounds in synthetic resin raw materials, avoiding secondary pollution, i.e., gas pretreatment technology for synthetic resin raw materials, is the key to accurately and comprehensively analyzing their volatile organic compounds. Summary of the Invention

[0007] To address the aforementioned shortcomings and deficiencies, the present invention aims to provide a method for testing volatile organic compounds in synthetic resin raw materials. The method provided by this invention can improve the comprehensiveness and accuracy of detection, while also simplifying operation and increasing efficiency.

[0008] To achieve the above objectives, the present invention provides a method for testing volatile organic compounds in synthetic resin raw materials, wherein the method includes:

[0009] S1: After mixing the synthetic resin particles with the solid phase extraction trap, seal the mixture so that the solid phase extraction trap can collect the volatile organic compounds in the synthetic resin particles.

[0010] S2: The solid-phase extraction trapping agent obtained in S1 is extracted at low temperature using an extraction solvent. After extraction, the supernatant is obtained by low-temperature centrifugation.

[0011] S3: The supernatant was analyzed by gas chromatography-high resolution mass spectrometry, and the obtained mass spectrum was then analyzed to obtain information on all volatile organic compounds and their contents.

[0012] As a specific embodiment of the method for testing volatile organic compounds in synthetic resin raw materials described above in this invention, in S1, synthetic resin particles and a solid-phase extraction trap are sealed in a gas sampling device, so that the solid-phase extraction trap collects volatile organic compounds in the synthetic resin particles.

[0013] As a specific embodiment of the method for testing volatile organic compounds in synthetic resin raw materials described above in this invention, in S1, the gas sampling device is a stainless steel container or a polytetrafluoroethylene gas bag with low permeability, low release, and low adsorption properties.

[0014] In a specific embodiment of the method for testing volatile organic compounds in synthetic resin raw materials described above in this invention, in S1, the volume of the gas sampling device is 1-10L.

[0015] As a specific embodiment of the method for testing volatile organic compounds in synthetic resin raw materials described above in this invention, in S1, the solid-phase extraction trapping agent includes one or a combination of two of activated carbon with a large surface area and silica with octadecyl groups grafted onto its surface.

[0016] In this invention, when using a combination of large-surface-area activated carbon and surface-grafted octadecyl silica as solid-phase extraction traps, the ratio of their amounts is not specifically required and can be determined according to actual operational needs. Furthermore, the surface-grafted octadecyl silica used in this invention is a conventional material, commercially available or prepared using conventional methods. The surface grafting rate of the surface-grafted octadecyl silica is not specifically required and can also be adjusted according to actual operational needs.

[0017] As a specific embodiment of the method for testing volatile organic compounds in synthetic resin raw materials described above in this invention, in S1, the sampling is carried out at room temperature for 24-168 hours, and the amount of synthetic resin particles used is 100-1000g.

[0018] Furthermore, this invention does not specify the exact ratio between the synthetic resin particles and the solid-phase extraction trap; the ratio can be determined based on actual operational needs.

[0019] As a specific embodiment of the method for testing volatile organic compounds in synthetic resin raw materials described above in this invention, in S1, the synthetic resin particles and the solid-phase extraction trap can be loaded into the gas sampling device together, or they can be loaded into the gas sampling device sequentially.

[0020] As a specific embodiment of the method for testing volatile organic compounds in synthetic resin raw materials described above in this invention, in S1, after the solid-phase extraction trap is taken out of the gas sampling device, if it is not analyzed immediately, it needs to be sealed and stored under low temperature conditions.

[0021] As a specific embodiment of the method for testing volatile organic compounds in synthetic resin raw materials described above in this invention, S2 includes:

[0022] The solid-phase extraction trap obtained in S1 was crushed and mixed with the extraction solvent for low-temperature extraction. After the extraction was completed, the extract was taken and centrifuged at low temperature to obtain the supernatant.

[0023] As a specific embodiment of the method for testing volatile organic compounds in synthetic resin raw materials described above in this invention, in step S2, the extraction solvent includes methanol, n-hexane, or dichloromethane.

[0024] In this invention, the amount of extraction solvent is not specifically required, and it can be adjusted according to actual operational needs.

[0025] As a specific embodiment of the method for testing volatile organic compounds in synthetic resin raw materials described above in this invention, in S2, the low-temperature extraction is extraction at 0-15℃ for 10-50 min.

[0026] As a specific embodiment of the method for testing volatile organic compounds in synthetic resin raw materials described above in this invention, in S2, the low-temperature extraction can be performed under ultrasonic conditions.

[0027] As a specific embodiment of the method for testing volatile organic compounds in synthetic resin raw materials described above in this invention, in S2, the temperature of the low-temperature centrifugation is 0-20℃, the rotation speed is 3000-30000 rpm, and the time is 10-50 min.

[0028] As a specific embodiment of the method for testing volatile organic compounds in synthetic resin raw materials described above in this invention, in step S3, gas chromatography-high resolution mass spectrometry is used to analyze the supernatant to obtain a mass spectrum of volatile organic compounds in the sample. The entire mass spectrum is analyzed and then matched with a standard spectral library to obtain information such as the chemical name and chemical formula of each component of the volatile organic compounds. At the same time, the relative content of each component of the volatile organic compounds is analyzed.

[0029] As a specific embodiment of the method for testing volatile organic compounds in synthetic resin raw materials described above in this invention, the method includes the following specific steps:

[0030] S1: The synthetic resin particles and solid phase extraction trap are sealed in a gas sampling device so that the solid phase extraction trap can collect the volatile organic compounds in the synthetic resin particles.

[0031] The gas sampling device is a stainless steel container or a polytetrafluoroethylene bag, and the volume of the gas sampling device is 1-10L.

[0032] The solid-phase extraction trapping agent includes one or a combination of two of activated carbon and surface-grafted octadecyl silica.

[0033] The sampling was conducted at room temperature for 24-168 hours, and the amount of synthetic resin particles used was 100-1000g.

[0034] S2: Crush the solid-phase extraction trap obtained in S1 and mix it with the extraction solvent for low-temperature extraction. After the extraction is completed, take the extract and centrifuge it at low temperature to obtain the supernatant.

[0035] The extraction solvent includes methanol, n-hexane, or dichloromethane;

[0036] The low-temperature extraction is performed at 0-15℃ for 10-50 min;

[0037] The low-temperature centrifugation is carried out at a temperature of 0-20℃, a rotation speed of 3000-30000 rpm, and a time of 10-50 min.

[0038] S3: The supernatant was analyzed by gas chromatography-high resolution mass spectrometry, and the obtained mass spectrum was then analyzed to obtain information on all volatile organic compounds and their contents.

[0039] In one specific embodiment of the method for testing volatile organic compounds in synthetic resin raw materials described above in this invention, the mass spectrometry resolution in the gas chromatography-high resolution mass spectrometry is not less than 60,000. For example, in some embodiments of this invention, the gas chromatography-high resolution mass spectrometry may be gas chromatography-quadrupole-electrostatic field orbital hydrazine mass spectrometry.

[0040] Compared with existing technologies, the beneficial effects of the method for testing volatile organic compounds in synthetic resin raw materials provided by this invention include:

[0041] 1. In the gas sampling process, in-situ sampling can be used to sample immediately after the sample is produced, or to sample and analyze samples from intermediate stages of the production process. In-situ sampling can avoid the loss of volatile organic compounds and secondary pollution in the sample, and is beneficial for the source analysis of odor substances.

[0042] 2. This method uses solid-phase extraction traps, which adsorb more comprehensively various compounds in the sample. Compared with the combination of Tenax traps and aldehyde-ketone derivatization tubes for sampling, this method greatly simplifies the sampling process. Compared with headspace sampling, this method has a larger sampling volume, which is tens or even hundreds of times larger than that of headspace sampling, and can collect volatile organic compounds with lower concentrations. It makes a significant contribution to the analysis of compounds with low concentrations and low thresholds, and to the odor analysis of synthetic resin raw materials.

[0043] 3. This method first performs low-temperature solvent extraction on the collected compounds, and then introduces the extract obtained from the low-temperature extraction into a gas chromatography-mass spectrometry tandem analysis system for analysis. This can avoid the discrimination of other sample introduction methods such as thermal desorption against high-boiling-point compounds, and can also effectively enrich low-boiling-point compounds into the mass spectrometry analysis system, ensuring that volatile organic compounds are fully introduced into the mass spectrometer and thus resolved.

[0044] 4. This method uses gas chromatography-quadrupole-electrostatic field orbital hydrazine mass spectrometry to analyze the supernatant. The mass spectrometry used is high-resolution mass spectrometry, which has high resolution, high sensitivity and high stability, and still responds to compounds with low concentration and weak signals. It can reduce matrix interference during sample analysis; it supports deconvolution spectrum analysis, so that compounds that are not well separated by the chromatographic column can be separated again, resulting in more accurate qualitative analysis of the standard spectral library; it reduces false positive results in the qualitative analysis of unknown substances; and it makes the qualitative analysis of unknown volatile organic compounds more accurate, thereby achieving comprehensive analysis of the volatile organic components of synthetic resin raw materials.

[0045] In summary, the method for testing volatile organic compounds (VOCs) in synthetic resin raw materials provided by this invention can avoid the loss of VOCs during storage and transportation, as well as secondary pollution from packaging and the environment. It also reduces the selectivity of VOCs during gas sample collection, resulting in a more comprehensive analysis of the VOC components in synthetic resin raw materials. Furthermore, this method can completely eliminate false positive results in VOC mass spectrometry qualitative analysis, ensuring high reliability of the analytical data. Finally, the data obtained by this method exhibits good repeatability and accuracy, and the operational process is simplified. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 This is a comparison chart of the peak area and intensity results of total volatile organic compounds in each sample per unit mass after internal standard calibration in Example 1 of the present invention.

[0048] Figure 2 These are the volatile organic compound spectra of the six test samples obtained in Example 2 of this invention.

[0049] Figure 3 This is the volatile organic compound spectrum of the sample in Comparative Example 1 of the present invention. Detailed Implementation

[0050] It should be noted that the term "comprising" and any variations thereof in the specification, claims, and accompanying drawings of this invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0051] The "range" disclosed in this invention is given in the form of a lower limit and an upper limit. It can be one or more lower limits and one or more upper limits, respectively. A given range is defined by selecting a lower limit and an upper limit. The selected lower and upper limits define the boundaries of the particular range. All ranges defined in this way are composable, meaning that any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for specific parameters, it is also expected that ranges of 60-110 and 80-120 are also expected. Furthermore, if the listed minimum range values ​​are 1 and 2, and the listed maximum range values ​​are 3, 4, and 5, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5.

[0052] In this invention, unless otherwise specified, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this invention, and "0-5" is simply a shortened representation of these numerical combinations.

[0053] In this invention, unless otherwise specified, all embodiments and preferred embodiments mentioned in this invention can be combined with each other to form new technical solutions.

[0054] In this invention, unless otherwise specified, all technical features and preferred features mentioned in this invention can be combined with each other to form new technical solutions.

[0055] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the appendices and embodiments. The embodiments described below are some, but not all, embodiments of this invention, and are only used to illustrate the invention, and should not be considered as limiting the scope of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0056] Example 1

[0057] This embodiment provides a method for testing volatile organic compounds in synthetic resin raw materials, wherein the method includes the following specific steps:

[0058] Gas sampling:

[0059] 1g of a composite solid-phase extraction trap consisting of surface-grafted octadecyl silica and activated carbon was placed in each of the seven 1L polytetrafluoroethylene gas bags. Then, 100g of each of the seven synthetic resin samples shown in Table 1 were placed in the bags, sealed, and collected at room temperature for 72 hours.

[0060] Table 1. Synthetic Resin Sample Numbers and Descriptions

[0061] Sample Description serial number After 0 hours of storage following the degradation of polypropylene by liquid peroxide, the polypropylene was dried. PP-L-0 After liquid peroxide degradation of polypropylene, it was stored for 13 hours. PP-L-13h After liquid peroxide degradation of polypropylene, it was stored for 27 hours. PP-L-27h Solid peroxide degradation of polypropylene after devolatilization and storage for 0 hours PP-S-0 Solid peroxide degradation of polypropylene after devolatilization and storage for 22 hours PP-S-22h Solid peroxide degradation of polypropylene after devolatilization and storage for 39 hours PP-S-39h Metallocene polypropylene PP-M

[0062] Solution extraction:

[0063] Take the above 7 solid phase extraction traps out of the polytetrafluoroethylene gas bag, put them into 7 centrifuge tubes respectively, and crush them;

[0064] Add 1 mL of methanol to each of the above 7 centrifuge tubes and extract by ultrasonication at 5°C for 50 min.

[0065] After extraction, the extracts from 7 centrifuge tubes were taken out and centrifuged at 5°C for 50 min at a speed of 12000 rpm.

[0066] Then, the supernatant from each of the seven centrifuge tubes was taken out, and the internal standard D4-1,4-dichlorobenzene was added to each tube to obtain the volatile organic compound extracts of the seven samples to be tested, which were then ready for mass spectrometry injection.

[0067] Mass spectrometry analysis:

[0068] The seven supernatant solutions were analyzed by gas chromatography-quadrupole-electrostatic field orbital hydrazine mass spectrometry (with a mass spectrometry resolution of 60,000) to obtain the volatile organic matter spectra of the seven test samples.

[0069] The gas chromatography-quadrupole-electrostatic field orbital hydrazine mass spectrometry analysis conditions include:

[0070] Gas chromatograph, model: TRACE1310;

[0071] Mass spectrometer, model: Exactive GC;

[0072] Gas chromatography conditions:

[0073] Inlet temperature: 250℃;

[0074] Temperature program: Hold at 35℃ for 5 minutes, then increase the temperature to 240℃ at a rate of 10℃ / min and hold for 5 minutes.

[0075] Column: DB-WAX;

[0076] Carrier gas: Helium;

[0077] Flow split ratio: 10;

[0078] Mass spectrometry conditions:

[0079] Ion source: EI;

[0080] Voltage: 70eV;

[0081] Ion source temperature: 250℃;

[0082] Transmission line temperature: 250℃;

[0083] Scan range: 35-300 m / z;

[0084] Resolution: 60000.

[0085] Using a deconvolution calculation method, the seven mass spectra were manually analyzed sequentially to obtain parameters such as retention time, retention index, exact fragment mass number, fragment mass deviation, and ion ratio of each component in the volatile organic compounds of the test samples. The retention time, retention index, exact fragment mass number, fragment mass deviation, and ion ratio were then matched with a standard spectral library to obtain the chemical name, molecular formula, structural formula, and CAS number of each component. Each component was then analyzed individually to obtain the unknown chemical information of the complete volatile organic compound composition, achieving full component analysis of the volatile organic compounds in the seven samples. The analysis results are shown in Table 2 below.

[0086] Table 2. Component analysis results of volatile organic compound (VOC) spectra of the seven samples in this embodiment.

[0087]

[0088]

[0089]

[0090]

[0091]

[0092] After convolving the chromatograms of each sample, the peak areas of all peaks for that sample are summed, divided by the peak area of ​​the internal standard peak, and the ratio is obtained. This ratio is then divided by the mass of each sample, i.e., the mass of the synthetic resin raw material, to obtain the peak area intensity of total volatile organic compounds (TVOCs) per unit mass sample after internal standard calibration. This allows for cross-sectional comparison of TVOC content between samples. In this embodiment, the peak area intensities of total volatile organic compounds for the seven samples are shown below. Figure 1 As shown. From Figure 1 As can be seen, after the synthetic resin particles are produced, their total volatile organic compounds (VOCs) initially increase, then decrease, and eventually stabilize with prolonged storage time. This conclusion aligns with actual industrial conditions. Furthermore, metallocene polypropylene is a well-known polypropylene with low VOC content. This embodiment fully demonstrates its low volatility, further indicating the reliability of the method provided in this invention.

[0093] Example 2

[0094] This embodiment provides a method for testing volatile organic compounds in synthetic resin raw materials, wherein the method includes the following specific steps:

[0095] Gas sampling:

[0096] 2g of a composite solid-phase extraction trap consisting of surface-grafted octadecyl silica and activated carbon was placed in each of six 10L polytetrafluoroethylene gas bags. Then, 1000g of each of the six synthetic resin raw material samples shown in Table 3 were placed in each bag, sealed, and collected at room temperature for 158 hours.

[0097] Table 3. Sample Numbers and Descriptions of Synthetic Resin Raw Materials

[0098]

[0099]

[0100] Solution extraction:

[0101] Take out the above 6 solid phase extraction traps from the polytetrafluoroethylene gas bag, put them into 6 centrifuge tubes respectively, and crush them;

[0102] Add 1 mL of methanol to each of the above 6 centrifuge tubes and perform ultrasonic extraction at 5°C for 50 min.

[0103] After extraction, the extracts from 6 centrifuge tubes were taken out and centrifuged at 5°C for 50 min at a speed of 12000 rpm.

[0104] The supernatant from each of the six centrifuge tubes was then taken out to obtain the volatile organic compound extracts of the six samples to be tested, which were then ready for mass spectrometry injection.

[0105] Mass spectrometry analysis:

[0106] Gas chromatography-quadrupole-electrostatic field orbital hydrazine mass spectrometry (with a mass spectrometry resolution of 60,000) was used to analyze the above six supernatant solutions, obtaining the volatile organic mass spectra of the six samples. Figure 2 As shown.

[0107] The gas chromatography-quadrupole-electrostatic field orbital hydrazine mass spectrometry analysis conditions include:

[0108] Gas chromatograph, model: TRACE1310;

[0109] Mass spectrometer, model: Exactive GC;

[0110] Gas chromatography conditions:

[0111] Inlet temperature: 250℃;

[0112] Temperature program: Hold at 35℃ for 5 minutes, then increase the temperature to 240℃ at a rate of 10℃ / min and hold for 5 minutes.

[0113] Column: DB-WAX;

[0114] Carrier gas: Helium;

[0115] Flow split ratio: 10;

[0116] Mass spectrometry conditions:

[0117] Ion source: EI;

[0118] Voltage: 70eV;

[0119] Ion source temperature: 250℃;

[0120] Transmission line temperature: 250℃;

[0121] Scan range: 35-300 m / z;

[0122] Resolution: 60000.

[0123] from Figure 2 As can be seen (shown in black boxes), in the first 10 minutes of retention time, compared to other peroxide-degraded polypropylenes (PP-A, PP-D, PP-C, PP-E, PP-F), metallocene polypropylene (PP-M) showed virtually no volatile organic compound leaching, which is consistent with experience.

[0124] Comparative Example 1

[0125] This comparative example provides a method for testing volatile organic compounds in synthetic resin raw materials. In this comparative example, the same sample PP-A as in Example 2 is used. The sample is taken, packaged, and transported to the laboratory for analysis and detection. However, in this comparative example, dynamic purge-trap-gas chromatography-mass spectrometry is used to determine the volatile organic compounds in synthetic resin particles, and the mass spectrometry is a single quadrupole mass spectrometer.

[0126] The method includes the following specific steps:

[0127] Take 1g of synthetic resin sample particles and place them into a dynamic purge-and-trap tube. After purge-and-trap and desorption, analyze the sample using a gas chromatography-mass spectrometry (GC-MS) system (a traditional mass spectrometer used in this field, distinct from high-resolution mass spectrometry) to obtain the volatile organic mass spectrum of the sample. Figure 3 As shown;

[0128] Among them, dynamic purge and capture adopts The sampler used was a Model 5200 purge-trap injector, and the gas chromatograph-mass spectrometer used was a Trace1300-ISQ. The testing conditions for the Model 5200 purge trap injector + Trace1300-ISQ gas chromatograph-gas chromatography-mass spectrometer include:

[0129] purge and capture procedures:

[0130] Purge gas: Nitrogen;

[0131] Purging temperature: 80℃;

[0132] Desorption temperature: 230℃; Desorption time: 3 min;

[0133] Gas chromatography procedure:

[0134] Inlet temperature: 240℃;

[0135] Pillar: TG-5MS;

[0136] Temperature program: 40℃ (1 min), then increase the temperature from 40℃ to 260℃ (5 min) at a rate of 8℃ / min.

[0137] Carrier gas: He;

[0138] Carrier gas flow rate: 1 mL / min;

[0139] Flow split ratio: 30;

[0140] Split flow rate: 30 mL / min;

[0141] Mass spectrometry procedure:

[0142] EI source;

[0143] Transmission line 250℃;

[0144] Ion source 280℃;

[0145] The mass number ranges from 33 to 600.

[0146] After full component analysis of the mass spectra, approximately 80 volatile organic compounds (VOCs) were obtained by matching with the standard spectral library. This indicates that the number of unknowns obtained after analysis using dynamic purge-trap combined with gas chromatography-quadrupole mass spectrometry (GC-MS) for the determination of VOCs in synthetic resin particles in this comparative example is significantly lower than the number obtained by the method in Example 1. Furthermore, the tandem GC-MS method, compared to the high-resolution mass spectrometry used in the examples (GC-quadrupole-electrostatic field orbital hydrazine mass spectrometry), cannot resolve the co-elution problem commonly encountered in gas chromatography. Therefore, the qualitative identification of unknowns retrieved from the spectral library is inaccurate.

[0147] Comparative Example 2

[0148] This comparative example provides a method for testing volatile organic compounds in synthetic resin raw materials. In this comparative example, six synthetic resin raw material samples of the same type as those in Example 1 (sample numbers and descriptions are shown in Table 4 below) were used, and the volatile organic compounds of the samples were determined by solid phase microextraction SPME-Arrow-gas chromatography-quadrupole-electrostatic field orbital hydrazine mass spectrometry, which is marked as Method A.

[0149] Table 4. Sample Numbers and Descriptions of Synthetic Resin Raw Materials

[0150] Sample Description serial number Peroxide-degraded polypropylene PP-1 Peroxide-degraded polypropylene PP-2 Peroxide-degraded polypropylene PP-3 Peroxide-degraded polypropylene PP-4 Peroxide-degraded polypropylene PP-5 Peroxide-degraded polypropylene PP-6

[0151] The method includes the following specific steps:

[0152] According to Table 4, 1g of synthetic resin particles were taken and extracted by solid phase microextraction (SPME-Arrow) and then analyzed by gas chromatography-quadrupole-electrostatic field orbital hydrazine mass spectrometry. Six mass spectra were obtained after the test.

[0153] Among them, solid-phase microextraction (SPME-Arrow) extraction specifically includes:

[0154] Take 1g of synthetic resin particles and incubate at 80℃ for 30min, adsorb SPME-Arrow for 10min, and desorb at 200℃ for 5min at the injection port.

[0155] The gas chromatography-quadrupole-electrostatic field orbital hydrazine mass spectrometer and its program conditions are the same as in Example 1, namely:

[0156] The gas chromatography-quadrupole-electrostatic field orbital hydrazine mass spectrometry analysis conditions include:

[0157] Gas chromatograph, model: TRACE1310;

[0158] Mass spectrometer, model: Exactive GC;

[0159] Gas chromatography conditions:

[0160] Inlet temperature: 200℃;

[0161] Temperature program: Hold at 35℃ for 5 minutes, then increase the temperature to 240℃ at a rate of 10℃ / min and hold for 5 minutes.

[0162] Column: DB-WAX;

[0163] Carrier gas: Helium;

[0164] Flow split ratio: 10;

[0165] Mass spectrometry conditions:

[0166] Ion source: EI;

[0167] Voltage: 70eV;

[0168] Ion source temperature: 250℃;

[0169] Transmission line temperature: 250℃;

[0170] Scan range: 35-300 m / z;

[0171] Resolution: 60000.

[0172] The six mass spectra were manually analyzed using a deconvolution calculation method to obtain parameters such as retention time, retention index, exact mass number, and ion ratio of each component in the volatile organic compounds of the samples. These parameters were then matched with a standard spectral library to obtain the chemical name, molecular formula, structural formula, and CAS number of each component. Each component was analyzed individually to obtain the unknown chemical information of the complete volatile organic compounds for each sample, ultimately yielding the A-method volatile organic compound analysis results for all six samples.

[0173] The six samples in Table 4 above were collected, extracted, and mass spectrographed in the same manner as in Example 1, and six mass spectra were obtained by analysis, which were marked as Method B.

[0174] Using a deconvolution calculation method, the above six mass spectra were manually analyzed sequentially to obtain parameters such as retention time, retention index, exact mass number, and ion ratio of each component in the volatile organic compounds of the test samples. These parameters were then matched with a standard spectral library to obtain the chemical name and molecular formula of each component. Each component was analyzed individually to obtain the unknown chemical information of the complete volatile organic compounds of each sample, ultimately yielding the complete volatile organic compound analysis results for the six samples using Method B.

[0175] The total number of volatile organic compounds obtained from the analysis of six samples using two methods is listed in Table 5.

[0176] Table 5. Results of the amount of volatile organic compounds obtained from the analysis of synthetic resin particles using two different methods in this comparative example.

[0177]

[0178] As shown in Table 5 above, when the gas was collected in the laboratory by solid-phase microextraction and analyzed by high-resolution mass spectrometry, the amount of volatile organic compounds obtained after analysis of the same sample was much less than the amount of organic compounds obtained by the test method provided in Example 1 of this invention. This indicates that in Method A of this comparative example, a large number of volatile organic compounds were not effectively collected and analyzed.

[0179] The above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, any substitution of equivalent components or equivalent changes and modifications made within the scope of protection of this patent should still fall within the scope of this patent. Furthermore, the technical features, technical features and technical inventions, and technical inventions in this invention can be freely combined and used.

Claims

1. A method for testing volatile organic compounds in synthetic resin raw materials, characterized in that, include: S1: After mixing the synthetic resin particles with the solid phase extraction trap, seal the mixture so that the solid phase extraction trap can collect the volatile organic compounds in the synthetic resin particles. In S1, the solid-phase extraction collector is silica with octadecyl grafted on the surface or a combination thereof with activated carbon, and the collection is performed at room temperature for 24-168 hours, with the amount of synthetic resin particles being 100-1000g. S2: The solid-phase extraction trap obtained in S1 is subjected to low-temperature extraction using an extraction solvent. After extraction, the supernatant is obtained by low-temperature centrifugation. In S2, the extraction solvent is methanol, the low-temperature extraction is performed at 0-15℃ for 10-50 min, and the low-temperature centrifugation is performed at 0-20℃, at a speed of 3000-30000 rpm, and for 10-50 min. S3: The supernatant was analyzed by gas chromatography-high resolution mass spectrometry, and the obtained mass spectrum was analyzed to obtain information on all volatile organic compounds and their contents. The gas chromatography column used was DB-WAX, and the temperature program was 35℃ for 5 min, then increased to 240℃ at a rate of 10℃ / min and held for 5 min. The high resolution mass spectrometry used an EI ion source with a scan range of 35-300 m / z.

2. The method for testing volatile organic compounds in synthetic resin raw materials according to claim 1, characterized in that, In S1, synthetic resin particles and a solid-phase extraction trap are sealed in a gas sampling device, allowing the solid-phase extraction trap to collect volatile organic compounds from the synthetic resin particles.

3. The method for testing volatile organic compounds in synthetic resin raw materials according to claim 2, characterized in that, In S1, the gas sampling device is a stainless steel container or a polytetrafluoroethylene gas bag.

4. The method for testing volatile organic compounds in synthetic resin raw materials according to claim 2, characterized in that, In S1, the volume of the gas sampling device is 1-10L.

5. The method for testing volatile organic compounds in synthetic resin raw materials according to claim 1, characterized in that, S2 include: The solid-phase extraction trap obtained in S1 was crushed and mixed with the extraction solvent for low-temperature extraction. After the extraction was completed, the extract was taken and centrifuged at low temperature to obtain the supernatant.

6. The method for testing volatile organic compounds in synthetic resin raw materials according to claim 1, characterized in that, The method includes the following specific steps: S1: The synthetic resin particles and solid phase extraction trap are sealed in a gas sampling device so that the solid phase extraction trap can collect the volatile organic compounds in the synthetic resin particles. The gas sampling device is a stainless steel container or a polytetrafluoroethylene bag, and the volume of the gas sampling device is 1-10L. The solid-phase extraction trapping agent is silica with octadecyl grafts or a combination thereof with activated carbon. The sampling was conducted at room temperature for 24-168 hours, and the amount of synthetic resin particles used was 100-1000g. S2: Crush the solid-phase extraction trap obtained in S1 and mix it with the extraction solvent for low-temperature extraction. After the extraction is completed, take the extract and centrifuge it at low temperature to obtain the supernatant. The extraction solvent is methanol; The low-temperature extraction is performed at 0-15℃ for 10-50 min; The low-temperature centrifugation is carried out at a temperature of 0-20℃, a rotation speed of 3000-30000 rpm, and a time of 10-50 min. S3: The supernatant was analyzed by gas chromatography-high resolution mass spectrometry, and the obtained mass spectrum was then analyzed to obtain information on all volatile organic compounds and their contents.

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