A method for quantifying short-chain chlorinated paraffins
By using gas chromatography-mass spectrometry in negative chemical ionization source mode, combined with nonlinear standard surface and internal standard method, the problem of low quantitative accuracy of short-chain chlorinated paraffins was solved, achieving a detection accuracy of 80%~120%, which is suitable for quantitative analysis of short-chain chlorinated paraffins in food, environment and daily products.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-11-27
- Publication Date
- 2026-03-03
AI Technical Summary
Existing technologies for detecting chlorinated paraffin content have low accuracy, especially quantitative methods for short-chain chlorinated paraffins, which have large errors and make it difficult to accurately distinguish the effects of carbon chain length and chlorine content.
Gas chromatography-mass spectrometry (GC-MS) in negative chemical ionization source mode was used to obtain standard solutions of short-chain chlorinated paraffins with different chlorine contents and concentrations. Nonlinear standard surfaces were plotted using the peak areas of at least four first and second quantitative ions, and quantitative analysis was performed using internal or external standard methods.
It improves the accuracy of short-chain chlorinated paraffin content detection to 80%~120%, effectively reducing quantitative errors caused by changes in carbon chain composition and chlorine content.
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Abstract
Description
Technical Field
[0001] This invention relates to a quantitative method for short-chain chlorinated paraffins, belonging to the field of analytical detection technology. Background Technology
[0002] Chlorinated paraffin (CP) S ) is the chain length in C 10 To C 30 A mixture of polychlorinated alkanes with varying degrees of chlorination (typically 30% to 75%), which can be classified into short-chain (C4-C4) alkanes based on their carbon chain length. 10 ~C 13 ), mid-chain (C) 14 ~C 17 ) and long chains (>C) 17 Chlorinated paraffin. Due to its low volatility, electrical insulation, flame retardancy, and low price, it is widely used in industrial production processes and consumer products.
[0003] The scientific community has gradually reached a consensus on the potential dangers of chlorinated paraffins to human and animal health. The bioaccumulation of chlorinated paraffins has been found in many foods and other organic substances, including but not limited to poultry, eggs, milk, and even breast milk; freshwater aquatic species, as well as poultry and terrestrial wildlife have also been contaminated. Chlorinated paraffins are bioaccumulative and exhibit persistence and long-distance migration in the environment. Evidence suggests that short-chain chlorinated paraffins can irritate the skin and eyes and increase the incidence of liver, thyroid, and kidney tumors.
[0004] Due to chlorinated paraffin (CP) S Organochlorinated paraffins (OCPs) contain various homologues and isomers; short-chain chlorinated paraffins alone have over 8,000 molecular structures, making them extremely complex and among the most complex organochlorine pollutants in the environment. Qualitative and quantitative analysis methods for OCPs face significant challenges. In samples where the carbon chain composition, proportions, and chlorine content of short-chain chlorinated paraffins are unknown, targeted quantification using a single chlorine content standard solution is difficult.
[0005] In EI-MSMS mode, short-chain chlorinated paraffins exhibit highly fragmented linear monomer molecules under 70 eV electron bombardment, resulting in a low mass-to-charge ratio (m / z) that fails to provide sufficient characteristic ions for qualitative identification. Quantitative analysis is also limited by medium-chain chlorinated paraffins (MCCPs). S The influence of other impurities is significant, and this method can be used to quantify the total amount of chlorinated paraffin (regardless of chain length).
[0006] In the NCI mode, short-chain chlorinated paraffins are mainly converted into [M-Cl]. - [M-HCl] - [MH] - [M+Cl] -[M+HCl] - [M+H] - [M-2Cl] - And [Cl2] - and [HCl2] - Plasma. No obvious fragmentation of the carbon backbone was observed; the fragmentation pattern depended to some extent on the amount of chlorine, with higher chlorine content in the homologues [M]. - The relative abundance is also higher. For most chlorinated paraffin homologues, the presence of a dominant molecular ion is a significant advantage, as it allows for the use of more specific ions for qualitative and quantitative analysis. However, a drawback of NCI determination of short-chain chlorinated paraffins is its susceptibility to chlorine content and the position of the chlorine atom on the carbon chain. The response value largely depends on the amount of chlorine, while the carbon chain length has a relatively small impact on the response value. High-chlorine-content short-chain chlorinated paraffins produce electrophilic ions with high response factors, while low-chlorinated paraffins have lower response factors.
[0007] In NCI mode, the response value is simultaneously affected by both the concentration of short-chain chlorinated paraffins and the chlorine content, and these two independent variables exhibit high multicollinearity. Existing two-dimensional linear quantitative methods first set one of these two independent variables constant. For example, ISO 18219-1:2021 Leather – Determination of chlorinated alkanes in leather – Part 1: Chromatography of short-chain chlorinated paraffins, where the chlorine content is fixed at 59%, and a standard curve is plotted for quantification. This quantitative method has low accuracy, ranging from 25% to 136% for determining short-chain chlorinated paraffins with different chlorine contents (51.5%–63%). Summary of the Invention
[0008] The problem the invention aims to solve
[0009] In view of the technical problems existing in the prior art, such as the low accuracy of current chlorinated paraffin content detection, the present invention first provides a quantitative method for short-chain chlorinated paraffins. The quantitative method for short-chain chlorinated paraffins of the present invention can effectively solve the problem of low accuracy in the detection of short-chain chlorinated paraffin content.
[0010] Solution for solving the problem
[0011] This invention provides a quantitative method for short-chain chlorinated paraffins, comprising the following steps:
[0012] Standard solutions with different chlorine contents and different short-chain chlorinated paraffin concentrations were obtained using short-chain chlorinated paraffin stock solutions;
[0013] The standard solution was detected by gas chromatography-mass spectrometry to obtain the sum of the peak areas corresponding to at least four first quantitative ions and the peak area corresponding to the second quantitative ion.
[0014] A standard surface is obtained based on the relationship between the sum of the peak areas corresponding to at least four first quantitative ions in the standard solution, the peak area corresponding to the second quantitative ion, and the concentration of short-chain chlorinated paraffins in each standard solution.
[0015] Prepare a sample solution to be tested, and use a gas chromatography-mass spectrometry (GC-MS) instrument to detect the sample solution to obtain the sum of the peak areas corresponding to at least four first quantitative ions and the peak area corresponding to the second quantitative ion. Based on the standard surface, obtain the concentration of short-chain chlorinated paraffins in the sample to be tested.
[0016] According to the quantitative method of the present invention, the short-chain chlorinated paraffin stock solution comprises C with a chlorine content of 51.5%. 10 ~C 13 Short-chain chlorinated paraffins, C with a chlorine content of 55.5% 10 ~C 13 Short-chain chlorinated paraffins and C with a chlorine content of 63% 10 ~C 13 Short-chain chlorinated paraffins.
[0017] According to the quantitative method of the present invention, the first quantitative ion includes a quantitative ion representing a compound with 10 carbon atoms, a quantitative ion representing a compound with 11 carbon atoms, a quantitative ion representing a compound with 12 carbon atoms, and a quantitative ion representing a compound with 13 carbon atoms.
[0018] According to the quantitative method of the present invention, the second quantitative ion includes one or more combinations of mass-to-charge ratios of 70, 71, 72 and 73.
[0019] According to the quantitative method of the present invention, the gas chromatography-mass spectrometry is used for detection in negative chemical ionization source mode.
[0020] According to the quantitative method of the present invention, the first quantitative ion to be detected in the sample to be tested is the same as the first quantitative ion in each standard solution.
[0021] According to the quantitative method of the present invention, the solvent used to dissolve the short-chain chlorinated paraffin and / or to prepare the standard solution includes one or more combinations of n-hexane, toluene, dichloromethane, and acetone.
[0022] According to the quantitative method of the present invention, the concentration of short-chain chlorinated paraffins is determined using an internal standard method or an external standard method.
[0023] According to the quantitative method of the present invention, when the internal standard method is used for detection, the internal standard used includes 1,2,3,4,5,6-hexachlorocyclohexane or 1,1,1,3,10,11-hexachloroundecane.
[0024] The effects of the invention
[0025] This invention employs a nonlinear surface quantitative method in a three-dimensional system, simultaneously considering two variables: concentration and chlorine content, thereby improving the accuracy of short-chain chlorinated paraffin content determination to 80%-120%.
[0026] This invention significantly improves the quantitative accuracy of short-chain chlorinated paraffins with low chlorine content, meeting the general requirements for quantitative detection. It can greatly reduce the quantitative error caused by differences in the carbon chain composition and content of short-chain chlorinated paraffins in the test sample and standard solution. Attached Figure Description
[0027] Figure 1 The standard surface of Example 1 is shown;
[0028] Figure 2 The standard surface of Example 2 is shown;
[0029] Figure 3 The total ion chromatogram (TIC) of the short-chain chlorinated paraffin standard solution of Example 1 with a concentration of 20 μg / mL and a chlorine content of 63% is shown.
[0030] Figure 4 The extraction ion chromatogram (EIC) of the short-chain chlorinated paraffin standard solution with a concentration of 20 μg / mL and a chlorine content of 63% in Example 1 is shown, with a mass-to-charge ratio (m / z) of 347 and 349.
[0031] Figure 5 The extraction ion chromatogram (EIC) of the short-chain chlorinated paraffin standard solution with a concentration of 20 μg / mL and a chlorine content of 63% in Example 1 is shown.
[0032] Figure 6 The extraction ion chromatogram (EIC) of the short-chain chlorinated paraffin standard solution with a concentration of 20 μg / mL and a chlorine content of 63% in Example 1 is shown, with a mass-to-charge ratio (m / z) of 375 and 377.
[0033] Figure 7 The extraction ion chromatogram (EIC) of the short-chain chlorinated paraffin standard solution with a concentration of 20 μg / mL and a chlorine content of 63% in Example 1 is shown, with a mass-to-charge ratio (m / z) of 389 and 391.
[0034] Figure 8 The total ion chromatogram (TIC) (including internal standard) of the short-chain chlorinated paraffin standard solution with a concentration of 80 μg / mL and a chlorine content of 59.25% in Example 2 is shown.
[0035] Figure 9 A partially enlarged total ion chromatogram (TIC) of the short-chain chlorinated paraffin standard solution of Example 2 with a concentration of 80 μg / mL and a chlorine content of 59.25% is shown (excluding internal standard).
[0036] Figure 10 The extracted ion chromatogram (EIC) of the internal standard 1,2,3,4,5,6-hexachlorocyclohexane with a mass-to-charge ratio (m / z) of 255 is shown in the short-chain chlorinated paraffin standard solution with a concentration of 80 μg / mL and a chlorine content of 59.25% in Example 2.
[0037] Figure 11 The extracted ion chromatogram (EIC) of the internal standard 1,2,3,4,5,6-hexachlorocyclohexane with a mass-to-charge ratio (m / z) of 70 is shown in the short-chain chlorinated paraffin standard solution with a concentration of 80 μg / mL and a chlorine content of 59.25% in Example 2.
[0038] Figure 12 The extraction ion chromatogram (EIC) of the short-chain chlorinated paraffin standard solution with a concentration of 80 μg / mL and a chlorine content of 59.25% in Example 2 is shown.
[0039] Figure 13 The extraction ion chromatogram (EIC) of the short-chain chlorinated paraffin standard solution with a concentration of 80 μg / mL and a chlorine content of 59.25% in Example 2 is shown, with a mass-to-charge ratio (m / z) of 313.
[0040] Figure 14 The extraction ion chromatogram (EIC) of the short-chain chlorinated paraffin standard solution with a concentration of 80 μg / mL and a chlorine content of 59.25% in Example 2 is shown, with a mass-to-charge ratio (m / z) of 293.
[0041] Figure 15 The extraction ion chromatogram (EIC) of the short-chain chlorinated paraffin standard solution with a concentration of 80 μg / mL and a chlorine content of 59.25% in Example 2 is shown, with a mass-to-charge ratio (m / z) of 277.
[0042] Figure 16The extraction ion chromatogram (EIC) of the short-chain chlorinated paraffin standard solution with a concentration of 80 μg / mL and a chlorine content of 59.25% in Example 2 is shown, with a mass-to-charge ratio (m / z) of 307.
[0043] Figure 17 The extraction ion chromatogram (EIC) of the short-chain chlorinated paraffin standard solution with a concentration of 80 μg / mL and a chlorine content of 59.25% in Example 2 is shown, with a mass-to-charge ratio (m / z) of 327.
[0044] Figure 18 The extraction ion chromatogram (EIC) of the short-chain chlorinated paraffin standard solution with a concentration of 80 μg / mL and a chlorine content of 59.25% in Example 2 is shown.
[0045] Figure 19 The extraction ion chromatogram (EIC) of the short-chain chlorinated paraffin standard solution with a concentration of 80 μg / mL and a chlorine content of 59.25% in Example 2 is shown, with a mass-to-charge ratio (m / z) of 347.
[0046] Figure 20 The extraction ion chromatogram (EIC) of the short-chain chlorinated paraffin standard solution with a concentration of 80 μg / mL and a chlorine content of 59.25% in Example 2 is shown, with a mass-to-charge ratio (m / z) of 381.
[0047] Figure 21 The extraction ion chromatogram (EIC) of the short-chain chlorinated paraffin standard solution with a concentration of 80 μg / mL and a chlorine content of 59.25% in Example 2 is shown, with a mass-to-charge ratio (m / z) of 341.
[0048] Figure 22 The extraction ion chromatogram (EIC) of the short-chain chlorinated paraffin standard solution with a concentration of 80 μg / mL and a chlorine content of 59.25% in Example 2 is shown, with a mass-to-charge ratio (m / z) of 321.
[0049] Figure 23 The extraction ion chromatogram (EIC) of the short-chain chlorinated paraffin standard solution with a concentration of 80 μg / mL and a chlorine content of 59.25% in Example 2 is shown, with a mass-to-charge ratio (m / z) of 375.
[0050] Figure 24 The extraction ion chromatogram (EIC) of the short-chain chlorinated paraffin standard solution with a concentration of 80 μg / mL and a chlorine content of 59.25% in Example 2 is shown, with a mass-to-charge ratio (m / z) of 355.
[0051] Figure 25 The extraction ion chromatogram (EIC) of the short-chain chlorinated paraffin standard solution with a concentration of 80 μg / mL and a chlorine content of 59.25% in Example 2 is shown, with a mass-to-charge ratio (m / z) of 395.
[0052] Figure 26 The extracted ion chromatogram (EIC) of the short-chain chlorinated paraffin standard solution of Example 2 with a mass-to-charge ratio (m / z) of 409 is shown.
[0053] Figure 27 The extraction ion chromatogram (EIC) of the short-chain chlorinated paraffin standard solution of Example 2 with a mass-to-charge ratio (m / z) of 415 is shown.
[0054] Figure 28 The extraction ion chromatogram (EIC) of the short-chain chlorinated paraffin standard solution with a concentration of 80 μg / mL and a chlorine content of 59.25% in Example 2 is shown, with a mass-to-charge ratio (m / z) of 389.
[0055] Figure 29 The extraction ion chromatogram (EIC) of the short-chain chlorinated paraffin standard solution with a concentration of 80 μg / mL and a chlorine content of 59.25% in Example 2 is shown, with a mass-to-charge ratio (m / z) of 429.
[0056] Figure 30 The extraction ion chromatogram (EIC) of the short-chain chlorinated paraffin standard solution with a concentration of 80 μg / mL and a chlorine content of 59.25% in Example 2 is shown, with a mass-to-charge ratio (m / z) of 423.
[0057] Figure 31 The extraction ion chromatogram (EIC) of the short-chain chlorinated paraffin standard solution with a concentration of 80 μg / mL and a chlorine content of 59.25% in Example 2 is shown, with a mass-to-charge ratio (m / z) of 443.
[0058] Figure 32 The extraction ion chromatogram (EIC) of the short-chain chlorinated paraffin standard solution with a concentration of 80 μg / mL and a chlorine content of 59.25% in Example 2 is shown, with a mass-to-charge ratio (m / z) of 449.
[0059] Figure 33The extraction ion chromatogram (EIC) of the short-chain chlorinated paraffin standard solution with a concentration of 80 μg / mL and a chlorine content of 59.25% in Example 2 is shown, with a mass-to-charge ratio (m / z) of 463.
[0060] Figure 34 The extraction ion chromatogram (EIC) of the short-chain chlorinated paraffin standard solution with a concentration of 80 μg / mL and a chlorine content of 59.25% in Example 2 is shown, with a mass-to-charge ratio (m / z) of 477.
[0061] Figure 35 The extraction ion chromatogram (EIC) of the short-chain chlorinated paraffin standard solution with a concentration of 80 μg / mL and a chlorine content of 59.25% in Example 2 is shown, with a mass-to-charge ratio (m / z) of 457.
[0062] Figure 36 The extracted ion chromatogram (EIC) of the short-chain chlorinated paraffin standard solution of Example 2 with a concentration of 80 μg / mL and a chlorine content of 59.25% is shown. The mass-to-charge ratio (m / z) is 491. Detailed Implementation
[0063] Various exemplary embodiments, features, and aspects of the present invention will be described in detail below. The term "exemplary" as used herein means "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior to or better than other embodiments.
[0064] Furthermore, to better illustrate the present invention, numerous specific details are set forth in the following detailed embodiments. Those skilled in the art should understand that the present invention can be practiced without certain specific details. In other instances, methods, means, apparatus, and steps well known to those skilled in the art have not been described in detail in order to highlight the spirit of the present invention.
[0065] Unless otherwise stated, all units used in this specification are international standard units, and all numerical values and ranges appearing in this invention should be understood to include systematic errors that are unavoidable in industrial production.
[0066] In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process.
[0067] In this specification, references to "some specific / preferred embodiments," "other specific / preferred embodiments," "implementation," etc., refer to specific elements (e.g., features, structures, properties, and / or characteristics) related to that embodiment, which are included in at least one of the embodiments described herein and may or may not be present in other embodiments. Furthermore, it should be understood that these elements may be combined in any suitable manner in various embodiments.
[0068] In this specification, the range of values referred to as "value A to value B" refers to the range including the endpoint values A and B.
[0069] In this instruction manual, when "room temperature" or "room temperature" is used, the temperature can be 15-25℃.
[0070] This invention provides a quantitative method for short-chain chlorinated paraffins, comprising the following steps:
[0071] Standard solutions with different chlorine contents and different short-chain chlorinated paraffin concentrations were obtained using short-chain chlorinated paraffin stock solutions;
[0072] The standard solution was detected by gas chromatography-mass spectrometry to obtain the sum of the peak areas corresponding to at least four first quantitative ions and the peak area corresponding to the second quantitative ion.
[0073] A standard surface is obtained based on the relationship between the sum of the peak areas corresponding to at least four first quantitative ions in the standard solution, the peak area corresponding to the second quantitative ion, and the concentration of short-chain chlorinated paraffins in each standard solution.
[0074] Prepare a sample solution to be tested, and use a gas chromatography-mass spectrometry (GC-MS) instrument to detect the sample solution to obtain the sum of the peak areas corresponding to at least four first quantitative ions and the peak area corresponding to the second quantitative ion. Based on the standard surface, obtain the concentration of short-chain chlorinated paraffins in the sample to be tested.
[0075] The accurate quantification of short-chain chlorinated paraffins is fundamental for surveying and controlling short-chain chlorinated paraffin pollution, testing daily necessities, and conducting pathological toxicity studies. Therefore, this invention is of great significance for the detection of short-chain chlorinated paraffin content. This invention employs a nonlinear surface quantification method in a three-dimensional system, simultaneously considering both concentration and chlorine content variables, thereby improving the accuracy of short-chain chlorinated paraffin content determination to 80%-120%.
[0076] The detection method of the present invention is applicable to C 10 ~C 13 Short-chain chlorinated paraffins.
[0077] In some specific embodiments, the short-chain chlorinated paraffin stock solution comprises C with a chlorine content of 51.5%.10 ~C 13 Short-chain chlorinated paraffins, C with a chlorine content of 55.5% 10 ~C 13 Short-chain chlorinated paraffins and C with a chlorine content of 63% 10 ~C 13 The present invention utilizes the aforementioned short-chain chlorinated paraffin stock solution to prepare standard solutions with different chlorine contents of the desired concentration, which can be used to plot standard surfaces.
[0078] The first quantitative ion used in the detection includes quantitative ions representing compounds with 10 carbon atoms, compounds with 11 carbon atoms, compounds with 12 carbon atoms, and compounds with 13 carbon atoms. When the first quantitative ion includes quantitative ions representing compounds with 10 carbon atoms, 11 carbon atoms, 12 carbon atoms, or 13 carbon atoms, the detection results are more accurate.
[0079] Specifically, the quantitative ions of the compounds representing 10 carbon atoms in this invention can be selected from qualitative ions with mass-to-charge ratios of 277, 279, 313, 315, 347, 349, 381, 383, 415, 417, 449, and 451, wherein the qualitative ions with high sensitivity are quantitative ions.
[0080] The quantitative ions representing compounds with 11 carbon atoms can be selected from qualitative ions with mass-to-charge ratios of 291, 293, 327, 329, 361, 363, 395, 397, 429, 431, 463, and 465. Among these, the ions with the highest sensitivity are the quantitative ions.
[0081] The quantitative ions representing compounds with 12 carbon atoms can be selected from qualitative ions with mass-to-charge ratios of 305, 307, 341, 343, 375, 377, 409, 411, 443, 445, 475, and 477. Among these, the qualitative ions with high sensitivity are the quantitative ions.
[0082] The quantitative ions representing 13 carbon atoms can be selected from qualitative ions with mass-to-charge ratios of 319, 321, 355, 357, 389, 391, 423, 425, 457, 459, 491, and 493. Among these, the qualitative ions with high sensitivity are the quantitative ions.
[0083] In some specific embodiments, the second quantitative ion includes one or more combinations of mass-to-charge ratios (m / z) of 70, 71, 72, and 73. The inventors of this invention have discovered that the sum of the peak areas corresponding to at least four first quantitative ions, the peak area corresponding to the second quantitative ion, and the concentration of short-chain chlorinated paraffins in the standard solution can form a standard surface. By utilizing the sum of the peak areas corresponding to at least four first quantitative ions, the peak area corresponding to the second quantitative ion, and the standard surface, the concentration of short-chain chlorinated paraffins in the sample can be rapidly obtained. When using two or more second quantitative ions, the sum of the peak areas of the two or more second quantitative ions can also be used.
[0084] For the standard surface, the standard surface of this invention is a nonlinear surface. The equation model used can be z = z0 + ax + by, z = z0 + ax + by + cxy, or z = z0 + ax + by + cxy. 2 +dy 2 One of +fxy, etc.
[0085] The gas chromatography-mass spectrometry (GC-MS) was used in negative chemical ionization mode. Specifically, the concentration of unknown short-chain chlorinated paraffins can be accurately obtained by using negative chemical ionization mode.
[0086] The present invention preferably uses ion monitoring as the detection method of gas chromatography-mass spectrometry to obtain the accurate concentration of short-chain chlorinated paraffins in the sample to be tested.
[0087] Specifically, in this invention, the chromatographic column used can be a capillary chromatographic column, such as Thermo Fisher TG-5SilMS.
[0088] Furthermore, this invention does not impose any particular limitations on the parameters of the gas chromatography-mass spectrometry (GC-MS) instrument; parameters that can accurately obtain results can be selected as needed.
[0089] Furthermore, during detection, an ionization method using a chemical (CI) source can be employed. Electrons emitted from the filament first ionize the reaction gas to generate reaction ions. These reaction ions then undergo ion-molecule reactions with the sample molecules, achieving sample molecule ionization. Because the ionization energy is significantly reduced, molecular ion peaks can be obtained, which is an important means of obtaining molecular weight information. This invention can use a CI source ionization method to select a negative ion source, resulting in not only good selectivity but also improved sensitivity. When using a CI source ionization method for detection, a reaction gas is required, such as methane, isobutane, or ammonia. This invention preferably uses methane as the reaction gas.
[0090] Furthermore, in the detection process, this invention uses a gas as the mobile phase, i.e., the carrier gas. The role of the carrier gas is to carry the gaseous sample or the vaporized gaseous sample together with the chromatographic column at a certain flow rate for separation. The separated components are then loaded into the detector for detection, and finally effluent from the chromatographic system for venting or collection. The carrier gas only serves a carrying function and does not participate in the separation process. Generally, commonly used carrier gases can be hydrogen, helium, argon, carbon dioxide, etc., and this invention preferably uses helium. Specifically, the flow rate of the carrier gas can be 0.8-1.5 mL / min.
[0091] Finally, the chromatographic-mass spectrometry interface temperature of this invention can be set to 250-300℃; the ion source temperature can also be set to 250-300℃. During detection, the gas chromatograph-mass spectrometer performs a programmed temperature increase according to the set temperature. Specifically, the initial temperature is 100-150℃, held for 0.5-3 min, and then increased to 290-310℃ at a rate of 5-20℃ / min, held for 5-10 min. Generally, the injection port temperature can be 250-300℃. In this invention, the injection method can be splitless, and the injection volume can be 0.5-2 μL.
[0092] Furthermore, in this invention, the first quantitative ion detected in the sample to be tested is the same as the first quantitative ion in each standard solution, thereby enabling more accurate detection results.
[0093] Furthermore, for the sample to be tested, if it is a short-chain chlorinated paraffin, it can be dissolved in a solvent. If other samples containing short-chain chlorinated paraffins are used, such as textiles, leather, rubber, or plastics, then the other samples need to be extracted with a solvent.
[0094] Furthermore, the present invention does not impose particular limitations on the solvents used for extracting test samples containing the aforementioned short-chain chlorinated paraffins and / or preparing standard solutions; any solvent may be selected as needed, as long as it can dissolve the short-chain chlorinated paraffins. Considering the accuracy of the test results, the solvents used in the present invention include one or more combinations of n-hexane, toluene, and dichloromethane.
[0095] In some specific embodiments, the present invention can use either the internal standard method or the external standard method to determine the concentration of short-chain chlorinated paraffins. Generally, the results obtained using the internal standard method are more accurate, while the external standard method does not require the use of an internal standard. Specifically, when using the internal standard method, the internal standard used includes 1,2,3,4,5,6-hexachlorocyclohexane or 1,1,1,3,10,11-hexachloroundecane.
[0096] For the standard surface of this application, when the external standard method is used for detection, the standard surface can be obtained by taking the sum of the peak areas corresponding to at least four first quantitative ions as the Y-axis, the peak area corresponding to the second quantitative ion as the X-axis, and the concentration of short-chain chlorinated paraffin in the standard solution as the Z-axis.
[0097] When the internal standard method is used for detection, the standard surface can be obtained by using the ratio of the sum of the peak areas corresponding to at least four first quantitative ions to the peak area of the internal standard as the Y-axis, the ratio of the peak area corresponding to the second quantitative ion to the peak area of the internal standard as the X-axis, and the concentration of short-chain chlorinated paraffin in the standard solution as the Z-axis.
[0098] In addition, the data processing software of the present invention can be one of Origin, SPSS, JMP, and MATLAB.
[0099] This invention significantly improves the quantitative accuracy of short-chain chlorinated paraffins with low chlorine content, meeting the general requirements for quantitative detection. It can greatly reduce the quantitative error caused by differences in the carbon chain composition and proportion of short-chain chlorinated paraffins in the test sample and standard solution.
[0100] The quantitative method for short-chain chlorinated paraffins of the present invention can be used to detect the content of short-chain chlorinated paraffins in food, environment, daily necessities (electronic appliances, textiles, leather, rubber and plastics, etc.) and short-chain chlorinated paraffin raw materials.
[0101] Example
[0102] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.
[0103] Example 1
[0104] 1. Reagents:
[0105] (1) n-Hexane, CAS No.: 110-54-3, chromatographic grade;
[0106] (2) Short-chain chlorinated paraffins with different chlorine contents (C 10 ~C 13 The stock solution, with a concentration of 100 μg / mL, is prepared in hexane and denoted as SCCP; among which, short-chain chlorinated paraffins (C...) with different chlorine contents... 10 ~C 13 The stock solution is available in the following three types:
[0107] ① Short-chain chlorinated paraffins with a chlorine content of 51.5% (C 10 ~C 13 This is recorded as: 51.5% SCCP;
[0108] ② Short-chain chlorinated paraffins with a chlorine content of 55.5% (C 10 ~C 13 This is recorded as: 55.5% SCCP;
[0109] ③ Short-chain chlorinated paraffins (C) with a chlorine content of 63.0% 10 ~C 13 This is recorded as: 63.0% SCCP;
[0110] 2. Instruments:
[0111] (1) Electronic balance: accuracy 0.1 mg;
[0112] (2) Pipettes: 100μL, 1000μL, 5000μL;
[0113] (3) Volumetric flasks: 2mL, 50mL, 100mL;
[0114] (4) Gas chromatography-negative chemical ionization mass spectrometry (GC-NCI-MS)
[0115] 3. Preparation of standard solutions
[0116] Standard solutions were prepared according to Table 1 to obtain 25 sets of standard solutions of short-chain chlorinated paraffins with different concentrations (see Table 1 for specific concentrations), which were used to obtain standard surfaces; among them, short-chain chlorinated paraffins with a chlorine content of 53.5% (C 10 ~C 13 ), composed of short-chain chlorinated paraffins (C) with a chlorine content of 51.5%. 10 ~C 13 ) and short-chain chlorinated paraffins (C) with a chlorine content of 55.5%. 10 ~C 13 Mix in equal proportions, denoted as: 53.5% SCCP; short-chain chlorinated paraffin (C) with a chlorine content of 59.25%. 10 ~C 13 ), composed of short-chain chlorinated paraffins (C) with a chlorine content of 55.5%. 10 ~C 13 ) and short-chain chlorinated paraffins with a chlorine content of 63% (C 10 ~C 13 Mix in equal proportions, denoted as: 59.25% SCCP.
[0117] Table 1
[0118]
[0119] 4. Parameters of the Gas Chromatography-Non-Gas Membrane Analyzer (GC-NCI-LRMS)
[0120] Capillary column: TG-5SILMS, 30m×0.25mm×0.25μm (or equivalent column);
[0121] Inlet temperature: 250℃;
[0122] Programmed temperature rise: Initial temperature 120℃, hold for 1 min, increase to 300℃ at 12℃ / min, hold for 7 min;
[0123] Solvent delay: 4 min;
[0124] Carrier gas: Helium (>99.999%);
[0125] Reactant gas: methane (>99.995%);
[0126] Chromatography-mass spectrometry interface temperature: 280℃;
[0127] Ion source temperature: 280℃;
[0128] Injection method: Splitless;
[0129] Carrier gas flow rate: 1.2 mL / min;
[0130] Injection volume: 1 μL;
[0131] Ionization method: CI;
[0132] Detection method: Selected ion monitoring (SIM);
[0133] Monitored ions: mass-to-charge ratio (m / z) of 347, 349, 361, 363, 375, 377, 389, 391, 70, and 72;
[0134] 5. Detection of standard solutions
[0135] According to the above-mentioned gas chromatography-mass spectrometry (GC-NCI-LRMS) parameters, the 25 sets of standard solutions prepared were tested and placed in sample vials. The peak areas of the 25 sets of standard solutions with mass-to-charge ratios (m / z) of 347, 349, 361, 363, 375, 377, 389, 391, 70 and 72 were measured using a GC-NCI-LRMS instrument.
[0136] 6. Drawing Standard Surfaces
[0137] The peak area corresponding to a mass-to-charge ratio (m / z) of 70 was selected as the x-axis (denoted as m / z70). The sum of the peak areas corresponding to mass-to-charge ratios (m / z) of 347, 361, 375, and 389 was selected as the y-axis (denoted as the sum of the four m / z values). The concentration of the standard solution to be tested in Table 1 was selected as the z-axis (denoted as SCCP). Specifically, according to the data shown in Table 2 below, the nonlinear surface (standard surface) was imported into Origin Pro 2021 to plot the equation, and the nonlinear surface (standard surface) was plotted. The results are as follows: Figure 1 As shown in Table 3.
[0138] Table 2
[0139]
[0140] Table 3
[0141]
[0142] 8. Determination of the sample to be tested
[0143] Five groups of blank leather samples were taken and spiked to obtain spiked leather samples. The spiked samples were: 51.5% SCCP at a concentration of 80 μg / mL, 55.5% SCCP at a concentration of 40 μg / mL, 63.0% SCCP at a concentration of 20 μg / mL, 52% commercially available industrial short-chain chlorinated paraffin at a concentration of 20 μg / mL, and 52% commercially available industrial short-chain chlorinated paraffin at a concentration of 80 μg / mL.
[0144] Preparation of extract: Weigh (0.5±0.001) g of the spiked leather sample using an analytical balance and place it in different reactors. Add n-hexane to 10 mL in each reactor and seal the reactor. Place the reactor in an ultrasonic water bath and extract the sample at (60±5) °C for (60±2) min. Cool to room temperature (below 27 °C). Purify with sulfuric acid. In another reactor, add 5 mL of the extraction solution and 1 mL of sulfuric acid, and react in a shaker for 10 min. Separate the aqueous and organic phases by centrifugation to obtain the organic phase, which is the sample to be tested.
[0145] Take 1 ml of the sample to be tested, and then perform the test according to the parameters of the gas chromatography-mass spectrometry (GC-NCI-LRMS) instrument described above. The results are shown in Table 4 below.
[0146] Table 4
[0147]
[0148] This invention uses recovery rate to examine the accuracy of the detection method. As shown in Table 4, the detection method of this invention can accurately detect the concentration of short-chain chlorinated paraffins in the test product, with an accuracy of 80% to 120%.
[0149] Example 2
[0150] 1. Reagents:
[0151] (1) n-Hexane, CAS No.: 110-54-3, chromatographic grade;
[0152] (2) Commercially available internal standard solution, 1,2,3,4,5,6-hexachlorocyclohexane (lindane), CAS No.: 58-89-9, concentration of 100 μg / mL, is referred to as: Lindane solution;
[0153] (3) Short-chain chlorinated paraffins (C) with different chlorine contents 10 ~C 13 The stock solution, with a concentration of 100 μg / mL, is prepared in hexane and denoted as SCCP; among which, short-chain chlorinated paraffins (C...) with different chlorine contents... 10 ~C 13 The stock solution is available in the following three types:
[0154] ① Short-chain chlorinated paraffins with a chlorine content of 51.5% (C 10 ~C 13 This is recorded as: 51.5% SCCP;
[0155] ② Short-chain chlorinated paraffins with a chlorine content of 55.5% (C 10 ~C 13 This is recorded as: 55.5% SCCP;
[0156] ③ Short-chain chlorinated paraffins (C) with a chlorine content of 63.0% 10 ~C 13 This is recorded as: 63.0% SCCP;
[0157] 2. Instruments:
[0158] (1) Electronic balance: accuracy 0.1 mg;
[0159] (2) Pipettes: 100μL, 1000μL, 5000μL;
[0160] (3) Volumetric flasks: 2mL, 50mL, 100mL;
[0161] (4) Gas chromatography-negative chemical ionization mass spectrometry (GC-NCI-MS)
[0162] 3. Preparation of standard solutions
[0163] Standard solutions were prepared according to the instructions in Table 5, resulting in 19 sets of standard solutions of short-chain chlorinated paraffins with different concentrations (see Table 5 for specific concentrations), which were used to obtain standard surfaces; among them, short-chain chlorinated paraffins with a chlorine content of 53.5% (C 10 ~C 13 ), composed of short-chain chlorinated paraffins (C) with a chlorine content of 51.5%. 10 ~C 13 ) and short-chain chlorinated paraffins (C) with a chlorine content of 55.5%. 10 ~C 13 Mix in equal proportions, denoted as: 53.5% SCCP; short-chain chlorinated paraffin (C) with a chlorine content of 59.25%. 10 ~C 13 ), composed of short-chain chlorinated paraffins (C) with a chlorine content of 55.5%. 10 ~C 13 ) and short-chain chlorinated paraffins with a chlorine content of 63% (C 10 ~C 13 Mix in equal proportions, denoted as: 59.25% SCCP.
[0164] Table 5
[0165]
[0166] 4. Parameters of the Gas Chromatography-Non-Gas Membrane Analyzer (GC-NCI-LRMS)
[0167] Capillary column: TG-5SILMS, 30m×0.25mm×0.25μm (or equivalent column);
[0168] Inlet temperature: 250℃;
[0169] Programmed temperature rise: Initial temperature 120℃, hold for 1 min, increase to 300℃ at 12℃ / min, hold for 7 min;
[0170] Solvent delay: 4 min;
[0171] Carrier gas: Helium (>99.999%);
[0172] Reactant gas: methane (>99.995%);
[0173] Chromatography-mass spectrometry interface temperature: 280℃;
[0174] Ion source temperature: 280℃;
[0175] Injection method: Splitless;
[0176] Carrier gas flow rate: 1.2 mL / min;
[0177] Injection volume: 1 μL;
[0178] Ionization method: CI;
[0179] Detection method: Selected ion monitoring (SIM);
[0180] Monitoring ions: 24 groups of first quantitative ions, second quantitative ions with mass-to-charge ratios (m / z) of 70 and 72, and characteristic ions representing internal standards with mass-to-charge ratios (m / z) of 255 and 257. Data were collected using two needles. The specific first and second quantitative ions monitored, along with the monitoring time, are shown in Table 6 below.
[0181] Table 6
[0182] Representative compound Mass-to-charge ratio (m / z) Mass-to-charge ratio (m / z) Points start time Points End Time <![CDATA[C 10 H 17 Cl5]]> 277 279 7.50 13.50 <![CDATA[C 10 H 16 Cl6]]> 313 315 8.50 13.50 <![CDATA[C 10 H 15 Cl7]]> 347 349 9.50 14.00 <![CDATA[C 10 H 14 Cl8]]> 381 383 10.50 15.25 <![CDATA[C 10 H 13 Cl9]]> 415 417 12.00 16.50 <![CDATA[C 10 H 12 Cl 10 ]]> 449 451 13.50 17.00 <![CDATA[C 11 H 19 Cl5]]> 293 291 8.25 14.50 <![CDATA[C 11 H 18 Cl6]]> 327 329 9.50 15.00 <![CDATA[C 11 H 17 Cl7]]> 361 363 10.50 16.00 <![CDATA[C 11 H 16 Cl8]]> 395 397 11.50 16.00 <![CDATA[C 11 H 15 Cl9]]> 429 431 12.50 17.00 <![CDATA[C 11 H 14 Cl 10 ]]> 463 465 13.50 18.50 <![CDATA[C 12 H 21 Cl5]]> 307 305 9.00 15.00 <![CDATA[C 12 H 20 Cl6]]> 341 343 10.50 16.50 <![CDATA[C 12 H 19 Cl7]]> 375 377 11.25 16.50 <![CDATA[C 12 H 18 Cl8]]> 409 411 12.25 17.50 <![CDATA[C 12 H 17 Cl9]]> 443 445 12.75 18.00 <![CDATA[C 12 H 16 Cl 10 ]]> 475 477 14.00 19.00 <![CDATA[C 13 H 23 Cl5]]> 321 319 10.00 16.00 <![CDATA[C 13 H 22 Cl6]]> 355 357 10.50 17.00 <![CDATA[C 13 H 21 Cl7]]> 389 391 12.00 17.00 <![CDATA[C 13 H 20 Cl8]]> 423 425 13.00 18.00 <![CDATA[C 13 H 19 Cl9]]> 459 457 13.50 18.75 <![CDATA[C 13 H 18 Cl 10 ]]> 493 491 14.50 19.25 AS(SCCP-Cl) 70 72 8.50 19.25 internal standard 255 257 — — AIS (Internal Standard - Cl) 70 72 — —
[0183] 5. Detection of standard solutions
[0184] According to the above-mentioned gas chromatography-mass spectrometry (GC-NCI-LRMS) parameters, the 19 sets of standard solutions prepared were tested and placed into sample vials. The peak areas of the first quantitative ions, the second quantitative ions with mass-to-charge ratios (m / z) of 70 and 72, and the characteristic ions with mass-to-charge ratios (m / z) of 255 and 257 representing the internal standards were measured in the 19 sets of standard solutions using a GC-NCI-LRMS instrument. All ions were scanned and data were collected in two separate injections.
[0185] 6. Drawing Standard Surfaces
[0186] The ratio of the peak area corresponding to a mass-to-charge ratio (m / z) of 70 to the peak area of the internal standard was selected as the x-axis (denoted as m / z70). The ratio of the sum of the peak areas of the 24 first quantitative ions to the peak area of the internal standard was selected as the y-axis (denoted as 24m / z sum). The concentration of the standard solution to be tested in Table 5 was selected as the z-axis (denoted as SCCP). Specifically, according to the data shown in Table 7 below, the nonlinear surface was imported into Origin Pro 2021 to draw a nonlinear surface, fit the equation, and draw the standard surface of the nonlinear surface. The results are as follows. Figure 2 As shown in Table 8.
[0187] Table 7
[0188]
[0189] Table 8
[0190]
[0191] Eleven blank leather samples were collected and spiked to obtain spiked leather samples. The spiked samples were: 51.5% SCCP at a concentration of 20 μg / mL, 51.5% SCCP at a concentration of 75 μg / mL, 53.5% SCCP at a concentration of 30 μg / mL, 53.5% SCCP at a concentration of 60 μg / mL, 55.5% SCCP at a concentration of 10 μg / mL, 55.5% SCCP at a concentration of 30 μg / mL, 55.5% SCCP at a concentration of 50 μg / mL, 59.25% SCCP at a concentration of 10 μg / mL, 59.25% SCCP at a concentration of 20 μg / mL, 52% commercially available industrial short-chain chlorinated paraffin-2 at a concentration of 70 μg / mL, and 52% commercially available industrial short-chain chlorinated paraffin-3 at a concentration of 70 μg / mL.
[0192] Preparation of extract: Weigh (0.5±0.001) g of the spiked leather sample using an analytical balance and place it in different reactors. Add n-hexane to 9.9 mL and 100 μL of internal standard solution to the reactors, and seal the reactors. Place the reactors in an ultrasonic water bath and extract the sample at (60±5) °C for (60±2) min. Cool to room temperature (below 27 °C). Purify with sulfuric acid. Add 5 mL of the extraction solution and 1 mL of sulfuric acid to another reactor and react in a shaker for 10 min. Separate the aqueous and organic phases by centrifugation to obtain the organic phase, which is the sample to be tested.
[0193] Take 1 ml of the sample to be tested, and then perform the test according to the parameters of the gas chromatography-mass spectrometry (GC-NCI-LRMS) instrument described above. The results are shown in Table 9 below.
[0194] Table 9
[0195]
[0196] This invention uses recovery rate to examine the accuracy of the detection method. As shown in Table 9, the detection method of this invention can accurately detect the content of short-chain chlorinated paraffins in the test product, with an accuracy of 80% to 120%.
[0197] It should be noted that although the technical solution of the present invention has been described with specific examples, those skilled in the art will understand that the present invention should not be limited thereto.
[0198] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.
Claims
1. A quantitative method for short-chain chlorinated paraffins, characterized in that, Includes the following steps: Standard solutions with different chlorine contents and different short-chain chlorinated paraffin concentrations were obtained using short-chain chlorinated paraffin stock solutions; The standard solution was detected by gas chromatography-mass spectrometry to obtain the sum of the peak areas corresponding to at least four first quantitative ions and the peak area corresponding to the second quantitative ion. A standard surface is obtained based on the relationship between the sum of the peak areas corresponding to at least four first quantitative ions in the standard solution, the peak area corresponding to the second quantitative ion, and the concentration of short-chain chlorinated paraffins in each standard solution. Prepare a sample solution to be tested, and use a gas chromatography-mass spectrometry (GC-MS) instrument to detect the sample solution to obtain the sum of the peak areas corresponding to at least four first quantitative ions and the peak area corresponding to the second quantitative ion. Based on the standard surface, obtain the concentration of short-chain chlorinated paraffins in the sample to be tested. The first quantitative ion includes quantitative ions representing compounds with 10 carbon atoms, quantitative ions representing compounds with 11 carbon atoms, quantitative ions representing compounds with 12 carbon atoms, and quantitative ions representing compounds with 13 carbon atoms. The second quantitative ion includes one or more combinations of mass-to-charge ratios of 70, 71, 72, and 73; The sample to be tested was leather.
2. The quantitative method according to claim 1, characterized in that, The short-chain chlorinated paraffin stock solution includes C with a chlorine content of 51.5%. 10 ~C 13 Short-chain chlorinated paraffins, C with a chlorine content of 55.5% 10 ~C 13 Short-chain chlorinated paraffins and C with a chlorine content of 63% 10 ~C 13 Short-chain chlorinated paraffins.
3. The quantitative method according to claim 1 or 2, characterized in that, The gas chromatography-mass spectrometry (GC-MS) instrument is used for detection in negative chemical ionization source mode.
4. The quantitative method according to claim 1 or 2, characterized in that, In the sample to be tested, the first quantitative ion to be detected is the same as the first quantitative ion of each standard solution.
5. The quantitative method according to claim 1 or 2, characterized in that, The solvents used to dissolve the short-chain chlorinated paraffins and / or to prepare standard solutions include one or more of n-hexane, toluene, dichloromethane, and acetone.
6. The quantitative method according to claim 1 or 2, characterized in that, The concentration of short-chain chlorinated paraffins was determined using either the internal standard method or the external standard method.
7. The quantitative method according to claim 6, characterized in that, When using the internal standard method for detection, the internal standard used includes 1,2,3,4,5,6-hexachlorocyclohexane or 1,1,1,3,10,11-hexachloroundecane.