A test method for polycyclic aromatic hydrocarbons in elastomers

Abstract

The present invention relates to the technical field of detection of polycyclic aromatic hydrocarbons, and in particular to a method for testing polycyclic aromatic hydrocarbons in an elastomer, comprising at least the following steps: (1) mixing an elastomer sample with a solvent and allowing the mixture to stand to obtain a sample solution; (2) adding an extractant to the sample solution for extraction, allowing the solution to stand for stratification, and taking the supernatant for gas chromatography-mass spectrometry detection and analysis. The method is simple and does not require additional complex pretreatment processes, thereby greatly improving detection efficiency and reducing detection costs. The method can be used for accurate quantitative detection of a variety of polycyclic aromatic hydrocarbons in elastomers, and is easy to promote daily monitoring of polycyclic aromatic hydrocarbons.

Description

Technical Field

[0001] The invention relates to the technical field of polycyclic aromatic hydrocarbon detection, and in particular to a method for testing polycyclic aromatic hydrocarbons in an elastomer. Background Art

[0002] Polycyclic aromatic hydrocarbons (PAHs) are compounds with two or more benzene rings and condensed rings in the molecule. They are usually found in petrochemical products, charcoal, creosote, drugs, dyes, rubber, plastics, lubricants, release agents, capacitor electrolytes, mineral oils, rust-proof oils, pesticides, incompletely burned organic compounds and other materials. They are bioresistant and cumulative, and have "three-cause" hazards. Therefore, all industries have put forward testing requirements for PAHs, including electronic and electrical products, cosmetics, water quality, soil and other fields.

[0003] A Chinese patent application (publication number CN106226418A) discloses a rapid, low-cost, simple and efficient method for detecting polycyclic aromatic hydrocarbons. The method includes acidification and impurity removal and acidification treatment steps, but the types of polycyclic aromatic hydrocarbons that can be detected are limited. A Chinese patent application (publication number CN116718686A) discloses a method for determining polycyclic aromatic hydrocarbons in thermoplastic elastomers, which mainly uses solid phase extraction to remove the interference of additives in thermoplastic elastomers, especially solid phase extraction columns dedicated to polycyclic aromatic hydrocarbons. Polymers with molecular imprinting on polycyclic aromatic hydrocarbon compounds are used to effectively adsorb polycyclic aromatic hydrocarbon compounds, directly remove interfering impurities, and directly improve the recovery rate and accuracy of polycyclic aromatic hydrocarbons. However, the sample pretreatment agent is easily lost during the detection process, the sample dosage is large, and the detection cost is relatively high, which is not easy to promote and implement.

[0004] Therefore, how to develop a simple, efficient and low-cost method for the quantitative detection of various PAHs in elastomers is of great significance for promoting the routine monitoring of PAHs. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a testing method for polycyclic aromatic hydrocarbons in elastomers. The method is simple, does not require additional complex pretreatment processes, greatly improves detection efficiency, and reduces detection costs. It can be used for accurate quantitative detection of various polycyclic aromatic hydrocarbons in elastomers, and is easy to promote daily monitoring of polycyclic aromatic hydrocarbons.

[0006] In one aspect, the present invention provides a method for testing polycyclic aromatic hydrocarbons in an elastomer, comprising at least the following steps:

[0007] (1) Mixing the elastomer sample with the solvent and allowing to stand to obtain a sample solution;

[0008] (2) Add an extractant to the sample solution for extraction. After standing for stratification, take the supernatant for gas chromatography-mass spectrometry analysis.

[0009] The elastomers in the present invention include thermoplastic elastomers and thermosetting elastomers;

[0010] Thermosetting elastomers include: styrene-butadiene rubber, butadiene rubber, isoprene rubber, ethylene-propylene rubber, butyl rubber, chloroprene rubber, and nitrile rubber.

[0011] Thermoplastic elastomers include: styrene-based thermoplastic elastomers (SBS, hydrogenated SBS (SEBS), SIS and hydrogenated SIS), polyurethane-based thermoplastic elastomers (TPU), polyolefin-based thermoplastic elastomers (TPO), and polyamide-based thermoplastic elastomers (TPEA).

[0012] As a preferred technical solution, the solvent is selected from at least one of methanol, ethanol, isopropanol, acetone, ketone, N-methylpyrrolidone and water.

[0013] Preferably, the solvent is methanol.

[0014] As a preferred technical solution, the ratio of the mass of the elastomer sample to the volume of the solvent is 1 g: (1-5) mL, preferably 1 g: (1-3) mL, and most preferably 1 g: 2 mL.

[0015] As a preferred technical solution, the standing condition is: standing in an oven at 40-60° C. for 2-4 days.

[0016] Preferably, the standing condition is: standing in an oven at 50° C. for 3 days.

[0017] As a preferred technical solution, the extractant includes at least n-hexane and water.

[0018] Preferably, the volume ratio of n-hexane to water is 1:(1-4), preferably 1:(1-2), and most preferably 1:1.

[0019] As a preferred technical solution, the extraction is in the form of shaking extraction, the extraction temperature is 15-30°C, and the extraction time is 15-60s.

[0020] Preferably, the extraction is in the form of shaking extraction, the extraction temperature is 25° C., and the extraction time is 30 s.

[0021] The polycyclic aromatic hydrocarbons in the present invention include naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, benzo[a]anthracene, chrysene, benzofluoranthene, benzo[a]pyrene, benzo[e]pyrene, indeno[1,2,3-cd]pyrene, benzo[ghi]perylene, dibenzo[a,h]anthracene, benzo[b]fluoranthene, benzo[k]fluoranthene and benzo[j]fluoranthene are isomers, and the three substances are combined as benzofluoranthene for calculation.

[0022] The test method provided by the present invention optimizes the pretreatment process and cooperates with the chromatographic detection condition control, so that the method is used for 18 kinds of polycyclic aromatic hydrocarbons in elastomers. The specificity, linearity, limit of quantification, accuracy, precision (repeatability and intermediate precision) and solution stability are all verified, and the detection and analysis results are accurate and reliable. Specifically, the elastomer sample is mixed with a solvent, and the sample solution is directly extracted with an extractant after standing, and then the sample can be injected for gas chromatography-mass spectrometry detection and analysis, which greatly simplifies the pretreatment process, does not require additional adsorption extraction columns, and avoids the loss of polycyclic aromatic hydrocarbons caused by multiple transfers and evaporation concentrations. In particular, after the elastomer sample is mixed with methanol and allowed to stand for 3 days, it can be extracted with a combination of n-hexane and water extractants for 15-60s for subsequent injection detection, ensuring that there is no interference in the subsequent target peak position, and the method has high accuracy and good precision. However, if only n-hexane is used as an extractant, the stability of the system is affected, resulting in smaller and smaller peaks of target compounds and an increase in QC quality control RSD.

[0023] As a preferred technical solution, the chromatographic parameters of the gas chromatography-mass spectrometry method include: an injection port temperature of 280-320°C; an injection mode of split injection, and a split ratio of (8-12):1; a transmission line temperature of 280-320°C; a chromatographic column of HP-5MS, 30m×0.25mm, 0.25μm; a column flow rate of 0.5-1.5mL / min; a heating program of: an initial temperature of 70-90°C, maintained for 1-3min, increased to 250-280°C at 15-25°C / min, increased to 300-320°C at 5-10°C / min, and maintained for 3-8min.

[0024] Preferably, the chromatographic parameters of the gas chromatography-mass spectrometry include: an injection port temperature of 300°C; an injection mode of split injection with a split ratio of 10:1; a transmission line temperature of 300°C; a chromatographic column of HP-5MS, 30m×0.25mm, 0.25μm; a column flow rate of 1.0mL / min; and a heating program of: initial temperature 80°C, maintained for 2min, increased to 260°C at 20°C / min, increased to 300°C at 5°C / min, and maintained for 5min.

[0025] As a preferred technical solution, the mass spectrometry parameters of the gas chromatography-mass spectrometry include: an ion source temperature of 200-250°C; a quadrupole temperature of 130-180°C; a solvent delay time of 3-5min; a scanning mode of selected ion monitoring, and the selected ions include 128 (NAP), 152 (ANY), 154 (ANA), 166 (FLU), 178 (ANT), 178 (PHE), 202 (FLT), 202 (PYR), 228 (BaA), 228 (CHR), 252 (BaP), 252 (BeP), 252 (BFA), 276 (BPE), 276 (IPY), 278 (DBA) m / z; and a scanning range of 50-350m / z.

[0026] Preferably, the mass spectrometry parameters of the gas chromatography-mass spectrometry include: an ion source temperature of 230°C; a quadrupole temperature of 150°C; a solvent delay time of 4 min; a scanning mode of selected ion monitoring, and selected ions include 128 (NAP), 152 (ANY), 154 (ANA), 166 (FLU), 178 (ANT), 178 (PHE), 202 (FLT), 202 (PYR), 228 (BaA), 228 (CHR), 252 (BaP), 252 (BeP), 252 (BFA), 276 (BPE), 276 (IPY), 278 (DBA) m / z; and a scanning range of 50~350m / z.

[0027] Furthermore, by optimizing the control of chromatography and mass spectrometry parameters, the injection repeatability and the repeatability of quality control solution were good, the method was specific, the linear correlation coefficients of 18 PAHs were all ≥0.993, the quantitative limit spike recovery rate was between 70% and 125%, with high accuracy and good precision.

[0028] Beneficial Effects

[0029] 1. The present invention provides a testing method for polycyclic aromatic hydrocarbons in elastomers. The method is simple and does not require additional complex pre-treatment processes, which greatly improves the detection efficiency and reduces the detection cost. It can be used for accurate quantitative detection of various polycyclic aromatic hydrocarbons in elastomers and is easy to promote daily monitoring of polycyclic aromatic hydrocarbons.

[0030] 2. The test method provided by the present invention optimizes the pretreatment process and coordinates the chromatographic detection conditions to verify the specificity, linearity, limit of quantification, accuracy, precision (repeatability and intermediate precision) and solution stability of 18 kinds of polycyclic aromatic hydrocarbons in elastomers, and the detection and analysis results are accurate and reliable.

[0031] 3. The present invention greatly simplifies the pretreatment process by mixing the elastomer sample with a solvent, letting it stand to obtain a sample solution, and then extracting it with an extractant before injecting it into a sample for gas chromatography-mass spectrometry detection and analysis. This does not require an additional adsorption extraction column and avoids the loss of polycyclic aromatic hydrocarbons caused by multiple transfers and evaporation concentrations.

[0032] 4. The present invention mixes the elastomer sample with methanol and allows it to stand for 3 days, then extracts it with a combination of n-hexane and water for 15-60s for subsequent sampling and detection, ensuring that there is no interference in the subsequent target peak position. The method has high accuracy and good precision.

[0033] 5. The present invention optimizes the chromatographic and mass spectrometric parameter control, and has good injection repeatability and quality control solution repeatability. The method is specific, the linear correlation coefficients of 18 polycyclic aromatic hydrocarbons are all ≥0.993, the quantitative limit spike recovery rate is between 70% and 125%, and the accuracy and precision are high. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The specificity chromatogram is the reagent blank solution.

[0035] Figure 2 It is the specific chromatogram of the standard curve solution (L-3).

[0036] Figure 3 It is the specific chromatogram of the sample solution.

[0037] Figure 4 The specific chromatogram is the quantitation limit spike solution. DETAILED DESCRIPTION

[0038] Example 1

[0039] Embodiment 1 of the present invention provides a method for testing polycyclic aromatic hydrocarbons in an elastomer, comprising the following steps:

[0040] (1) Mixing the elastomer sample with the solvent and allowing to stand to obtain a sample solution;

[0041] (2) Add an extractant to the sample solution for extraction. After standing for stratification, take the supernatant for gas chromatography-mass spectrometry analysis.

[0042] The elastomer is a butyl rubber stopper.

[0043] The solvent is methanol, and the ratio of the mass of the elastomer sample to the volume of the solvent is 1 g:2 mL.

[0044] The standing condition is: standing in an oven at 50° C. for 3 days.

[0045] The extractant is n-hexane and water, and the volume ratio of n-hexane to water is 1:1.

[0046] The extraction is in the form of shaking extraction, the extraction temperature is 25° C., and the extraction time is 30 seconds.

[0047] The chromatographic parameters of the gas chromatography-mass spectrometry method include: an injection port temperature of 300°C; an injection mode of split injection with a split ratio of 10:1; an injection volume of 1 μL; a carrier gas of He; a transmission line temperature of 300°C; a chromatographic column of HP-5MS, 30m×0.25mm, 0.25μm; a column flow rate of 1.0mL / min; and a heating program of: an initial temperature of 80°C, maintained for 2min, increased to 260°C at 20°C / min, increased to 300°C at 5°C / min, and maintained for 5min.

[0048] The mass spectrometry parameters of the gas chromatography-mass spectrometry method include: an ion source temperature of 230° C.; a quadrupole temperature of 150° C.; a solvent delay time of 4 min; a scanning mode of selected ion monitoring, and selected ions include 128 (NAP), 152 (ANY), 154 (ANA), 166 (FLU), 178 (ANT), 178 (PHE), 202 (FLT), 202 (PYR), 228 (BaA), 228 (CHR), 252 (BaP), 252 (BeP), 252 (BFA), 276 (BPE), 276 (IPY), and 278 (DBA) m / z; and a scanning range of 50 to 350 m / z.

[0049] Comparative Example 1

[0050] Comparative Example 1 of the present invention provides a method for testing polycyclic aromatic hydrocarbons in an elastomer, and its specific implementation method is the same as that of Example 1, except that the extractant is n-hexane.

[0051] Performance Testing

[0052] 1. The method provided in Example 1 was verified by the following methodology.

[0053] 1. Materials and methods

[0054] 1. Standard material information. For standard material information, please refer to Table 1-1 below.

[0055] Table 1-1 Standard substance information

[0056]

[0057] Table 1-2 Target information

[0058]

[0059] 2. Standard test solution information: For standard test solution information, please refer to Table 1-3 below.

[0060] Table 1-3 Standard test solution information

[0061]

[0062] 3. Instrument information: For instrument information, please refer to Table 1-4 below.

[0063] Table 1-4 Instrument information

[0064]

[0065] 4. Reagent information: For reagent information, please refer to Table 1-5 below.

[0066] Table 1-5 Reagent information

[0067]

[0068] 2. Verification process

[0069] 1. Preparation of analytical solution

[0070] 1.1 Diluent: n-hexane

[0071] 1.2 Extraction agent: purified water, n-hexane

[0072] 1.3 Standard substance solution

[0073] 1.3.1 18 PAHs Mixed Standard A

[0074] Measure 100.0ul of 18 kinds of PAHs mixed standard into a 10ml volumetric flask, dilute to the mark with n-hexane, mix well, and mark as 18 kinds of PAHs mixed standard A.

[0075] 1.3.2 18 kinds of PAHs mixed standard B

[0076] Measure 100.0ul of 18 kinds of PAHs mixed standard into a 10ml volumetric flask, dilute to the mark with n-hexane, mix well, and mark as 18 kinds of PAHs mixed standard B.

[0077] 1.4 Standard curve solution

[0078] According to Table 2-1, measure 18 kinds of PAHs mixed standard A into different 10ml volumetric bottles, dilute to scale with diluent, shake well, and prepare standard curve solution. The concentration of standard substances in the standard curve solution is shown in Table 2-2 below.

[0079] Table 2-1 Standard curve solution preparation table

[0080]

[0081] Table 2-2 Concentration of standard substances in standard curve solution

[0082]

[0083] 1.5 System Suitability (SST) Solution

[0084] Take 1 ml of L-3 into a sample injection vial.

[0085] 1.6 Quality Control (QC) Solution

[0086] Take 1 ml of L-3 into a sample injection vial.

[0087] 1.7 Limit of Quantitation (LOQ) Solution

[0088] L-1 was taken as the quantitative limit solution.

[0089] 1.8 Sample stock solution

[0090] Take 500 ml of methanol in a 500 ml solvent bottle.

[0091] 1.9 Sample solution

[0092] Take 1g of elastomer and put it into 2ml of methanol, and place it in a 50℃ oven for 3 days; take 5.000ml into a sample bottle, add 5.000ml of n-hexane and purified water respectively, shake and extract for 30s, let it stand until layers are separated, and take 1ml of the supernatant into an injection vial.

[0093] 1.10 Reagent blank solution

[0094] Pipette 5.000 ml of methanol into a sample bottle, add 5.000 ml each of n-hexane and purified water, shake and extract for 30 seconds, let stand until layers are separated, and take 1 ml of the supernatant into an injection vial.

[0095] 1.11 Accuracy Solution

[0096] 1.11.1 Low concentration level accuracy solution

[0097] Low concentration horizontal accuracy solution: Measure 5.000ml of the sample mother solution into a 10ml volumetric bottle, add 50.0μl of 18 kinds of PAHs mixed standard A, add the sample mother solution to dilute to the scale, and shake well. Pipette 5.000ml of the above solution into a sample bottle, then add 5.000ml of the extractant n-hexane and purified water, shake and extract for 30s, let stand until stratification, and take 1ml of the supernatant into a sample vial. Prepare a total of 3 solutions in parallel with the same method, and obtain low concentration horizontal accuracy solution 1 to low concentration horizontal accuracy solution 3 in turn.

[0098] 1.11.2 Medium concentration level accuracy solution

[0099] Medium concentration level accuracy solution: Measure 5.000ml of the sample mother solution into a 10ml volumetric bottle, add 150.0μl of 18 kinds of PAHs mixed standard A, add the sample mother solution to dilute to the scale, and shake well. Pipette 5.000ml of the above solution into a sample bottle, then add 5.000ml of the extractant n-hexane and purified water, shake and extract for 30s, let stand until stratification, and take 1ml of the supernatant into a sample vial. Prepare a total of 3 solutions in parallel with the same method, and obtain medium concentration level accuracy solution 1 to medium concentration level accuracy solution 3 in turn.

[0100] 1.11.3 High Concentration Level Accuracy Solution

[0101] High concentration horizontal accuracy solution: Measure 5.000ml of the sample mother solution into a 10ml volumetric bottle, add 200.0μl of 18 kinds of PAHs mixed standard A, add the sample mother solution to dilute to the scale, and shake well. Pipette 5.000ml of the above solution into a sample bottle, then add 5.000ml of the extractant n-hexane and purified water, shake and extract for 30s, let stand until stratification, and take 1ml of the supernatant into a sample vial. Prepare a total of 3 solutions in parallel using the same method, and obtain high concentration horizontal accuracy solution 1 to high concentration horizontal accuracy solution 3 in turn.

[0102] 1.12 Limit of Quantitation Spiked Solution

[0103] The low concentration level accuracy solution 1 to the low concentration level accuracy solution 3 were used as the quantitation limit spike solution 1 to the quantitation limit spike solution 3.

[0104] 1.13 Proprietary solution

[0105] The reagent blank solution, sample solution 1, standard curve solution (L-3) and quantitation limit spike solution 1 were used as specific solutions.

[0106] 1.14 Reproducible solution

[0107] Measure 5.000ml of the sample mother solution into a 10ml volumetric bottle, add 150.0μl of 18 kinds of PAHs mixed standard A, add the sample mother solution to dilute to the scale, and shake well. Pipette 5.000ml of the above solution into a sample bottle, add 5.000ml of the extractant n-hexane and purified water, shake and extract for 30s, let stand until stratification, and take 1ml of the supernatant into a sample vial. Prepare a total of 6 solutions in parallel with the same method, and obtain repeatability solution 1 to repeatability solution 6 in turn.

[0108] 1.15 Solution stability

[0109] The above-mentioned reproducible solutions 1 to 6 were placed at 2 to 8° C. for 8 days to obtain solution stability solution 1 to solution stability solution 6, respectively.

[0110] 1.16 Intermediate precision solution

[0111] Prepared by the second analyst on a different day, the same instrument was used to inject and analyze the sample. Measure 5.000ml of the sample mother solution into a 10ml volumetric bottle, add 150.0μl of 18 kinds of PAHs mixed standard B, add the sample mother solution to dilute to the scale, and shake well. Pipette 5.000ml of the above solution into a sample bottle, then add 5.000ml of the extractant n-hexane and purified water, shake and extract for 30s, let stand until stratification, and take 1ml of the upper solution into the injection vial. Prepare a total of 6 solutions in parallel with the same method, and obtain intermediate precision solution 1 to intermediate precision solution 6 in turn.

[0112] 2 Instrumental analysis method

[0113] Please refer to Table 2-3 and Table 2-4 below for instrument analysis method parameters.

[0114] Table 2-3 Chromatographic parameters of GC-MS

[0115]

[0116] Table 2-4 GC-MS mass spectrometry parameters

[0117]

[0118] 3. Results Analysis

[0119] 1. System applicability

[0120] 1.1 Results Analysis

[0121] 1.1.1 Injection repeatability

[0122] Acceptance criteria for injection repeatability: The RSD of the target peak area shall not be greater than 10%. The analysis results show that the injection repeatability meets the requirements of the acceptance criteria. The results of injection repeatability are shown in Table 3-1 below.

[0123] Table 3-1 Results of injection repeatability

[0124]

[0125] 1.1.2 Quality Control

[0126] The repeatability acceptance standard of the quality control solution is: the RSD of the target peak area shall not be greater than 15%.

[0127] The analysis results showed that the quality control test results met the requirements of the acceptance criteria.

[0128] The repeatability results of the quality control solution are shown in Tables 3-2 and 3-3 below.

[0129] Table 3-2 Results of repeatability of quality control solution -1

[0130]

[0131] Table 3-3 Results of repeatability of quality control solution-2

[0132]

[0133] 2. Exclusivity

[0134] 2.1 Results Analysis

[0135] Acceptance criteria for specificity: There should be no obvious interference in the peak position of the target substance in the reagent blank solution, standard curve solution (L-3), sample solution and quantitative limit spike solution; the measured value of the target substance in the reagent blank solution should not be greater than 1 / 3 of the quantitative limit. The analysis results show that the specificity test results meet the requirements of the acceptance criteria. The specificity results are shown in Tables 3-4 and 3-5 below, and the specificity spectrum is shown in Figure 1-4 .

[0136] Table 3-4 Specificity results 1

[0137]

[0138] Table 3-5 Specificity results 2

[0139]

[0140] 3.1 Results Analysis

[0141] Acceptance criteria for linearity: The correlation coefficient must not be less than 0.99. The analysis results show that the linearity test results meet the requirements of the acceptance criteria. The linearity results are shown in Table 3-6 below.

[0142] Table 3-6 Linear results

[0143]

[0144] 4 Limit of Quantitation

[0145] 4.1 Results Analysis

[0146] Report the signal-to-noise ratio of the target in the quantitation limit solution, and calculate the recovery rate and RSD of the recovery rate of the target in the quantitation limit spike solution. Acceptance criteria for the quantitation limit: the signal-to-noise ratio must not be less than 10; the quantitation limit spike recovery rate is between 70% and 125%, and the RSD of the recovery rate must not be greater than 15%. The analysis results show that the quantitation limit test results meet the requirements of the acceptance criteria. The results of the quantitation limit are shown in Table 3-7 below. The results of the quantitation limit spike solution are shown in Table 3-8 below.

[0147] Table 3-7 Results of quantitation limit

[0148]

[0149] Table 3-8 Results of quantitation limit spike solution

[0150]

[0151] 5. Accuracy

[0152] 5.1 Results Analysis

[0153] Acceptance criteria for accuracy: recovery rate is between 70% and 125%, and the RSD of recovery rate shall not be greater than 15%.

[0154] The analysis results show that the results of the accuracy test meet the requirements of the acceptance criteria. The accuracy results are shown in Table 3-9 below.

[0155] Table 3-9 Results of accuracy solution

[0156]

[0157]

[0158]

[0159]

[0160]

[0161]

[0162] 5.2 Calculation formula

[0163] Recovery rate = (measured amount (μg) - background (μg)) ÷ added (μg) × 100%;

[0164] When the target compound was not detected in the sample solution, the recovery rate was calculated with 0.000 as the background.

[0165] 6. Precision (repeatability)

[0166] 6.1 Results Analysis

[0167] Repeatability acceptance criteria: RSD shall not be greater than 15%. The analysis results show that the precision (repeatability) test results meet the requirements of the acceptance criteria. The repeatability results are shown in Table 3-10 below. Table 3-10 Repeatability results.

[0168] Table 3-10 Repeatability results

[0169]

[0170] 7Precision (intermediate precision)

[0171] 7.1 Results Analysis

[0172] Intermediate precision acceptance criteria: RSD shall not be greater than 22%. The analysis results show that the precision (intermediate precision) test results meet the requirements of the acceptance criteria. The intermediate precision results are shown in Table 3-11 below.

[0173] Table 3-11 Intermediate precision results

[0174]

[0175] 8 Solution stability

[0176] 8.1 Results Analysis

[0177] Solution stability acceptance criteria: RSD shall not be greater than 22%. The analysis results show that the solution stability test results meet the requirements of the acceptance criteria. The results of solution stability are shown in Table 3-12 below.

[0178] Table 3-12 Solution stability results

[0179]

[0180] 9 Conclusion

[0181] Gas chromatography-mass spectrometry (GC-MS) was used to validate the specificity, linearity, limit of quantification, accuracy, precision (repeatability and intermediate precision) and solution stability of the analytical method for 18 PAHs in the methanol extract of elastomers. The results of all validation indicators met the requirements of the acceptance criteria.

[0182] 2. Methodological verification was performed on the method provided in Comparative Example 1. The verification method was the same as that in Example 1. The system applicability did not meet the requirements. Before testing with the method provided in Comparative Example 1, the results of the injection repeatability were shown in Table 3-13. The results showed that the system was stable. A quality control test was performed. The repeatability results of the quality control solution were shown in Table 3-14 (QC-1). tRSD(%)-1 was qualified. After testing with the method provided in Comparative Example 1, a quality control test was performed. The repeatability results of the quality control solution were shown in Table 3-14 (QC-1). tRSD(%)-1 was unqualified, resulting in an unstable detection system. No other methodological verification was performed.

[0183] Table 3-13 Results of injection repeatability

[0184]

[0185] Table 3-14 Results of repeatability of quality control solution

[0186]

Claims

1. A method for testing polycyclic aromatic hydrocarbons in elastomers, characterized in that: At least the following steps are included: (1) Mixing the elastomer sample with the solvent and allowing to stand to obtain a sample solution; (2) Adding an extractant to the sample solution for extraction, standing and separating the layers, and taking the supernatant for gas chromatography-mass spectrometry analysis; the solvent is methanol; the standing condition is: standing in an oven at 40-60°C for 2-4 days; the extractant is n-hexane and water, and the volume ratio of n-hexane to water is 1:(1-4); the extraction is in the form of shaking extraction, the extraction temperature is 15-30°C, and the extraction time is 15-60s; the elastomer is a thermosetting elastomer.

2. The method for testing polycyclic aromatic hydrocarbons in elastomers according to claim 1, characterized in that: The ratio of the mass of the elastomer sample to the volume of the solvent is 1 g: (1-5) mL.

3. The method for testing polycyclic aromatic hydrocarbons in elastomers according to claim 1, characterized in that: The chromatographic parameters of the gas chromatography-mass spectrometry method include: an injection port temperature of 280-320°C; an injection mode of split injection, and a split ratio of (8-12):1; a transmission line temperature of 280-320°C; a chromatographic column of HP-5MS, 30m×0.25mm, 0.25μm; a column flow rate of 0.5-1.5mL / min; a heating program of: an initial temperature of 70-90°C, maintained for 1-3min, increased to 250-280°C at 15-25°C / min, increased to 300-320°C at 5-10°C / min, and maintained for 3-8min.

4. The method for testing polycyclic aromatic hydrocarbons in elastomers according to claim 3, characterized in that: The injection port temperature is 300°C; the split ratio is 10:1; the transfer line temperature is 300°C; the column flow rate is 1.0 mL / min; the heating program is: initial temperature 80°C, maintained for 2 min, increased to 260°C at 20°C / min, increased to 300°C at 5°C / min, and maintained for 5 min.

5. The method for testing polycyclic aromatic hydrocarbons in elastomers according to claim 1, characterized in that: The mass spectrometry parameters of the gas chromatography-mass spectrometry method include: an ion source temperature of 200-250° C.; a quadrupole temperature of 130-180° C.; a solvent delay time of 3-5 min; a scanning mode of selected ion monitoring, and the selected ions include: NAP: 128 m / z, ANY: 152 m / z, ANA: 154 m / z, FLU: 166 m / z, ANT: 178 m / z, PHE: 178 m / z, FLT: 202 m / z, PYR: 202 m / z, BaA: 228 m / z, CHR: 228 m / z, BaP: 252 m / z, BeP: 252 m / z, BFA: 252 m / z, BPE: 276 m / z, IPY: 276 m / z, and DBA: 278 m / z.

6. The method for testing polycyclic aromatic hydrocarbons in elastomers according to claim 5, characterized in that: The ion source temperature was 230° C.; the quadrupole temperature was 150° C.; and the solvent delay time was 4 min.

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