Method for detecting and analyzing ethylene oxide

Abstract

The invention discloses an ethylene oxide detection and analysis method, which belongs to the technical field of detection and analysis, and comprises the following steps: weighing a sample to be detected, adding deuterated internal standard ethylene oxide-D4, and dissolving the sample with a low-temperature mixed solvent to obtain a sample solution; uniformly mixing the sample solution, adding a purifying material for purifying, uniformly mixing and centrifuging to obtain supernate; putting a part of the supernate into a small solid-phase microextraction bottle, adding sodium chloride, and uniformly mixing to obtain a solution to be detected; placing the small solid-phase microextraction bottle filled with the solution to be detected on a gas chromatograph-tandem mass spectrometer with a CTC automatic solid-phase microextraction sampling device, and extracting and detecting the prepared solution to be detected; and analyzing the data acquired by the mass spectrum by utilizing Agilent MassHunter data processing software. According to the method, volatile components in a sample are enriched, concentrated and then detected, the residual amount of ethylene oxide in the fat-soluble plant extract can be directly and quantitatively analyzed, the sensitivity is high, and the accuracy is good.

Description

Technical Field

[0001] The invention relates to the technical field of detection and analysis, in particular to a detection and analysis method for ethylene oxide. Background Art

[0002] Plant extracts are products that use plants as raw materials and undergo a physical and chemical extraction and separation process to obtain one or more active ingredients in plants. Fat-soluble plant extracts are a type of plant extract that is insoluble in water but soluble in fat and non-polar organic solvents. Ethylene oxide (EO) is a broad-spectrum fungicide with strong penetration and sterilization capabilities, and is widely used in industry, medicine, food, and pharmaceuticals. After food is sterilized with ethylene oxide, ethylene oxide reacts with the matrix to produce more toxic 2-chloroethanol (2-CE). Excessive ethylene oxide and 2-chloroethanol not only cause acute poisoning, but also have certain genetic toxicity and carcinogenicity. Due to the special production process, pepper extracts, tomato extracts, marigold extracts, and pepper extracts are easily contaminated by ethylene oxide during the production process, which affects product quality. European customers require that the ethylene oxide content in plant extracts is less than 0.01 mg / kg.

[0003] The molecular formula of ethylene oxide is C2H4O, the relative molecular mass is 44.052, and the boiling point is 10.7°C. Because its relative molecular mass is extremely small and close to the relative molecular mass of other reagents such as acetonitrile, it is difficult to separate it on a mass spectrum. Because of its extremely low boiling point, it is easy to volatilize at room temperature and is easily lost during operation, which will lead to inaccurate quantification.

[0004] The Chinese invention patent with publication number CN117929548A is named "A method for determining ethylene oxide". The sample matrix of this method is milk. Ethylene oxide is converted into 2-chloroethanol, and the actual content of ethylene oxide in the sample to be tested is obtained by subtraction. The pre-treatment process of this method is complicated and the content of ethylene oxide cannot be directly detected. Wu Wanqin et al. used headspace / gas chromatography-mass spectrometry to determine the residual amount of ethylene oxide and its metabolite 2-chloroethanol in food. The sample was not enriched and detected by single-stage mass spectrometry. The sensitivity was relatively low and the matrix effect was strong. Xiao Guiying directly used SPME combined with gas chromatography-tandem mass spectrometry to detect ethylene oxide and its metabolite 2-chloroethanol in food without extracting the sample. Wang Weixi et al. used QuEChERS-gas chromatography-tandem mass spectrometry to simultaneously determine ethylene oxide and 2-chloroethanol in food. However, when the sample matrix to be tested is a fat-soluble plant extract, the matrix is complex and contains many volatile components, which can easily interfere with the detection of ethylene oxide. Therefore, this method cannot effectively detect the content of ethylene oxide in fat-soluble plant extracts. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a method for detecting and analyzing ethylene oxide. Based on the ability of solid-phase microextraction fibers to enrich and concentrate volatile substances, after purification to remove impurity interference by the deuterated internal standard method, the volatile components in the sample are enriched and concentrated and then detected, so as to directly quantitatively analyze the residual amount of ethylene oxide in fat-soluble plant extracts.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0007] A method for detecting and analyzing ethylene oxide, comprising the following steps:

[0008] Step 1, weigh a quantitative sample to be tested, add deuterated internal standard ethylene oxide-D4, and dissolve the sample with a low-temperature mixed solvent to obtain a sample solution;

[0009] Step 2, mix the sample solution evenly, add purification materials for purification, mix evenly and centrifuge to obtain a supernatant;

[0010] Step 3, take a part of the supernatant and place it in a solid-phase microextraction vial, add sodium chloride, and mix evenly to obtain a test solution;

[0011] Step 4, place the solid-phase microextraction vial containing the test solution on a gas chromatography-tandem mass spectrometer equipped with a CTC automatic solid-phase microextraction injection device to extract and detect the prepared test solution;

[0012] Step 5, use Agilent MassHunter data processing software to analyze the data collected by the mass spectrometer.

[0013] A further improvement of the technical solution of the present invention is that: in Step 1, the sample to be tested is a fat-soluble plant extract sample; the fat-soluble plant extract includes but is not limited to pepper extract, tomato extract, marigold extract, and Chinese prickly ash extract.

[0014] A further improvement of the technical solution of the present invention is that: in Step 1, the weighed amount of the sample to be tested is 4 - 5 g and is placed in a 50 mL centrifuge tube.

[0015] A further improvement of the technical solution of the present invention is that: in Step 1, the added standard concentration of the deuterated internal standard ethylene oxide-D4 is 2 mg / L, and the added standard volume is 0.05 - 0.1 mL.

[0016] A further improvement of the technical solution of the present invention is that: in Step 1, the low-temperature mixed solvent is a mixed solution of water, methanol, and dimethyl sulfoxide that has been placed in a refrigerator at 4 - 8 °C for at least 2 h; the volume ratio of water:methanol:dimethyl sulfoxide in the mixed solution is 1:2:7; the added amount of the low-temperature mixed solvent is 20 - 25 mL.

[0017] A further improvement of the technical solution of the present invention lies in: in step 2, the specific operation is as follows: after vortexing the sample solution for 30 s, add the purification material and then vortex for another 30 s, and centrifuge at a centrifugal speed of 10000 r / min for 5 min under the condition of 4°C.

[0018] A further improvement of the technical solution of the present invention lies in: the purification material includes N-propylethylenediamine, silica gel-bonded octadecyl microspheres and graphitized carbon black, wherein the addition amount of N-propylethylenediamine is 100-125 mg, the addition amount of silica gel-bonded octadecyl microspheres is 100-125 mg, and the addition amount of graphitized carbon black is 100-125 mg.

[0019] A further improvement of the technical solution of the present invention lies in: in step 3, it specifically includes: pipette 5 mL of the supernatant into a 20 mL solid-phase microextraction vial, add 1 g of sodium chloride, tighten the bottle cap, and vortex thoroughly to obtain the test solution.

[0020] A further improvement of the technical solution of the present invention lies in: in step 4, the specific instrument conditions of the gas chromatography-tandem mass spectrometry instrument with a CTC automatic solid-phase microextraction injector are as follows:

[0021] (a) CTC conditions: Agilent SPME Arrow carbon WR / PDMS, 1.10 mm outer diameter, 120 μm stationary phase thickness, the injector is SPME-STD-V7.3; heating oven temperature: 80°C; heating time: 30 min; SPME fiber aging temperature: 270°C; aging time: 5 min;

[0022] (b) Using a programmed temperature large-volume injection port: programmed temperature conditions: initial temperature 80°C, hold for 0.25 min, heat to 220°C at a rate of 900°C / min; split ratio: 3:1;

[0023] (c) Chromatographic column: DB-624UI, column length 60 m, inner diameter 0.25 mm, film thickness 1.40 μm; programmed temperature conditions: initial temperature 40°C, hold for 5 min, heat to 220°C at a rate of 25°C / min, hold for 3 min, heat to 240°C at a rate of 20°C / min, hold for 5 min;

[0024] (d) Mass spectrometry conditions: EI source, electron energy of 70 eV, ion source temperature: 230 °C, transfer line temperature: 280 °C, solvent delay of 7.5 min, quantitative ion pair of ethylene oxide: 44.0 / 29.0, collision energy of 5 eV, qualitative ion pairs: 44.0 / 15.0, 44.0 / 42.0, 44.0 / 43.0, collision energies: 17 eV, 7 eV, 3 eV respectively; quantitative ion pair of deuterated ethylene oxide-D4: 48.0 / 30.0, collision energy of 5 eV, qualitative ion pair: 48.0 / 16.0, collision energy of 40 eV.

[0025] A further improvement of the technical solution of the present invention lies in that: during the detection and analysis, the detection and analysis of two samples need to be carried out in parallel, and the average value is taken as the detection result; at the same time, two parallel detections are carried out for 1 spiked level; at the same time, 1 blank detection also needs to be carried out.

[0026] Due to the adoption of the above technical solution, the technical progress achieved by the present invention is:

[0027] 1. Based on the ability of the solid-phase microextraction fiber to enrich and concentrate volatile substances, the present invention uses the deuterated internal standard method to enrich and concentrate the volatile components in the sample to be tested after purifying and removing impurity interference, and then detects them, and can directly quantitatively analyze the residual amount of ethylene oxide in the fat-soluble plant extract.

[0028] 2. The present invention fills the technical gap of determining ethylene oxide in fat-soluble plant extracts by solid-phase microextraction. After purifying and removing impurities from the sample, it uses the solid-phase microextraction mode for extraction and on-machine detection, enriches and concentrates the target substance to the greatest extent, reduces the impurity interference in the sample, and effectively improves the detection accuracy of the sample.

[0029] 3. The present invention uses deuterated internal standard for quantitative analysis of ethylene oxide; uses a pre-cooled mixed solvent to dissolve the sample to be tested, effectively reducing the volatilization of ethylene oxide.

[0030] 4. The present invention purifies the sample through N-propylethylenediamine, silica-bonded octadecyl microspheres and graphitized carbon black, minimizing the interference of impurities on ethylene oxide, and adding sodium chloride to the purified solution to improve the response sensitivity of ethylene oxide;

[0031] 5. The present invention uses a solid-phase microextraction device to enrich, concentrate and extract ethylene oxide, greatly improving the detection sensitivity.

[0032] 6. The present invention effectively separates the chromatographic peaks of ethylene oxide and the volatile components in the fat-soluble plant extract by optimizing the large-volume injection port and the chromatographic column programmed temperature conditions; by optimizing the quantitative and qualitative ion pairs of ethylene oxide and the collision energy, the ion pairs and collision energy with the best response are screened out. Brief Description of the Drawings

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings;

[0034] Figure 1 It is the chromatogram of ethylene oxide in the spiked recovery sample of 0.01 mg / kg pepper extract in Example 1 of the present invention;

[0035] Figure 2 It is the chromatogram of deuterated internal standard ethylene oxide-D4 in the pepper extract sample in Example 1 of the present invention. Detailed Embodiments

[0036] It should be noted that the terms "including" and "having" and any variations thereof in the description and claims of the present invention and the above drawings are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0037] The present invention will be further described in detail below with reference to the drawings and embodiments:

[0038] In order to verify the feasibility of a method for detecting and analyzing ethylene oxide provided by the present invention, since fat-soluble plant extracts (including but not limited to pepper extract, tomato extract, marigold extract and Chinese prickly ash extract) can all be detected and analyzed for ethylene oxide by this method. For more intuitive detection, in the present invention, the spiked recovery experiment and the embodiments all use pepper extract as the sample to be detected. The experimental process of the spiked recovery experiment is as follows:

[0039] Step 1: Weigh 5 g of 2 chili extract samples into 50-mL centrifuge tubes respectively for parallel detection. Then weigh 5 g of 18 identical chili extracts into 50-mL centrifuge tubes respectively for spike recovery experiments. The spike recovery experiments are carried out with spike levels of 0.01 mg / kg, 0.02 mg / kg, and 0.05 mg / kg (add 0.005, 0.01, and 0.025 mL of 10 mg / L ethylene oxide standard solution respectively), and 6 parallel detections are carried out for each spike level. At the same time, prepare a 50-mL centrifuge tube without weighing samples for the whole-process blank experiment (to detect whether the experimental process will contaminate the samples). Add deuterated internal standard ethylene oxide-D4 (spike concentration is 2 mg / L, spike volume is 0.05 mL) to the above 21 50-mL centrifuge tubes respectively, and then add 25 mL of a water / methanol / dimethyl sulfoxide (volume ratio 1:2:7) mixed solvent (previously placed in a 4°C refrigerator for 2 h) to dissolve the samples to obtain chili extract sample solutions.

[0040] Step 2: After vortexing the 21 chili extract sample solutions for 30 s, add 125 mg of N-propylethylenediamine, 125 mg of silica-bonded octadecyl microspheres, and 125 mg of graphitized carbon black purification materials respectively, vortex for 30 s, and centrifuge at a refrigerated centrifuge speed of 10000 r / min for 5 min at 4°C to obtain the supernatant.

[0041] Step 3: Weigh 5 mL of the supernatant obtained by the above centrifugation into 20-mL solid-phase microextraction vials respectively, add 1 g of sodium chloride, tighten the bottle caps, and fully vortex and mix to obtain the test solution.

[0042] Step 4: Use a gas chromatography-tandem mass spectrometry instrument (equipped with a CTC automatic solid-phase microextraction injection device) to extract and detect the prepared test solution.

[0043] The specific instrument conditions are as follows:

[0044] (a) CTC conditions: Agilent SPME Arrow carbon WR / PDMS, 1.10 mm outer diameter, 120 μm stationary phase thickness, the injector is SPME-STD-V7.3; heating oven temperature: 80°C; heating time: 30 min; SPME fiber aging temperature: 270°C; aging time: 5 min.

[0045] (b) Use a programmed temperature large-volume injection port: Programmed temperature conditions: initial temperature 80°C, hold for 0.25 min, and increase the temperature to 220°C at a rate of 900°C / min; split ratio: 3:1.

[0046] (c) Chromatographic column: DB-624UI, column length 60 m, inner diameter 0.25 mm, film thickness 1.40 μm; Program temperature conditions: initial temperature 40 °C, hold for 5 min, heat at 25 °C / min to 220 °C, hold for 3 min, heat at 20 °C / min to 240 °C, hold for 5 min.

[0047] (d) Mass spectrometry conditions: EI source, electron energy 70 eV, ion source temperature: 230 °C, transfer line temperature 280 °C, solvent delay 7.5 min, quantitative ion pair of ethylene oxide is 44.0 / 29.0, collision energy is 5 eV, qualitative ion pairs are 44.0 / 15.0, 44.0 / 42.0, 44.0 / 43.0 respectively, collision energies are 17 eV, 7 eV, 3 eV respectively; quantitative ion pair of deuterated ethylene oxide-D4 is 48.0 / 30.0, collision energy is 5 eV, qualitative ion pair is 48.0 / 16.0, collision energy is 40 eV.

[0048] Step 5, use Agilent MassHunter data processing software to analyze the data collected by mass spectrometry. The linear range of ethylene oxide is 0.002 - 0.4 mg / L, and the limit of quantification is 0.01 mg / kg.

[0049] Step 6, analyze the results of the chili extract sample and the spike recovery analysis results at 3 spike levels. The results are shown in Table 1.

[0050] Table 1 Results of spike recovery experiment

[0051]

[0052] It is stipulated in the Guidelines for the Validation and Verification of Chemical Analysis Methods in Conformity Assessment GB / T 27417-2017 that when the spike amount is below 0.1 mg / kg, the spike recovery range is 60% - 120%. The detection precision at the 0.01 mg / kg level should be within 21%, and the detection precision at the 0.01 mg / kg - 0.1 mg / kg level should be within 15%. As can be seen from Table 1, the spike recovery of ethylene oxide in the chili extract is between 97.6% - 105.0%, and the relative standard deviation is between 2.41% - 6.64%, meeting the requirements of GB / T 27417-2017. The detection and analysis method for ethylene oxide provided by the present invention can be used for the routine detection of ethylene oxide in chili extracts.

[0053] Example 1

[0054] A detection and analysis method for ethylene oxide, comprising the following steps:

[0055] Step 1: Weigh 5 g of 2 chili extracts respectively into 50 mL centrifuge tubes for parallel detection. At the same time, weigh 5 g of 2 chili extracts respectively into 50 mL centrifuge tubes for the spike recovery experiment at 0.01 mg / kg (add 0.005 mL of 10 mg / L ethylene oxide standard solution), and conduct 2 parallel detections for each spike level. At the same time, prepare a 50 mL centrifuge tube without weighing samples for the whole-process blank detection. Add deuterated internal standard ethylene oxide-D4 (spike concentration 2 mg / L, spike volume 0.05 mL) to the above 5 50 mL centrifuge tubes respectively, and then add 25 mL of water / methanol / dimethyl sulfoxide (volume ratio 1:2:7) mixed solvent (previously placed in a 4 °C refrigerator for 2 h) to dissolve the samples to obtain chili extract sample solutions.

[0056] Step 2: After vortexing the 5 chili extract sample solutions for 30 s, add 125 mg of N-propylethylenediamine, 125 mg of silica-bonded octadecyl microspheres, and 125 mg of graphitized carbon black purification materials respectively, vortex for 30 s, and centrifuge at a freezing centrifugation speed of 10000 r / min for 5 min at 4 °C to obtain the supernatant.

[0057] Step 3: Weigh 5 mL of the supernatant obtained by centrifugation above into 20 mL solid-phase microextraction vials respectively, add 1 g of sodium chloride respectively, tighten the bottle caps, and fully vortex and mix to obtain the test solution.

[0058] Step 4: Use a gas chromatography-tandem mass spectrometry instrument (equipped with a CTC automatic solid-phase microextraction injection device) to extract and detect the prepared test solution. The specific instrument conditions are as follows:

[0059] (a) CTC conditions: Agilent SPME Arrow carbon WR / PDMS, 1.10 mm outer diameter, 120 μm stationary phase thickness, injector is SPME-STD-V7.3; heating oven temperature: 80 °C; heating time: 30 min; SPME fiber aging temperature: 270 °C; aging time: 5 min.

[0060] (b) Use a programmed temperature large-volume injection port: Programmed temperature conditions: initial temperature 80 °C, hold for 0.25 min, increase the temperature to 220 °C at a rate of 900 °C / min; split ratio: 3:1.

[0061] (c) Chromatographic column: DB-624UI, column length 60 m, inner diameter 0.25 mm, film thickness 1.40 μm; Programmed temperature conditions: initial temperature 40 °C, hold for 5 min, increase the temperature to 220 °C at a rate of 25 °C / min, hold for 3 min, increase the temperature to 240 °C at a rate of 20 °C / min, and hold for 5 min.

[0062] (d) Mass spectrometry conditions: EI source, electron energy of 70 eV, ion source temperature: 230 °C, transfer line temperature: 280 °C, solvent delay of 7.5 min, quantitative ion pair of ethylene oxide is 44.0 / 29.0, collision energy is 5 eV, qualitative ion pairs are 44.0 / 15.0, 44.0 / 42.0, 44.0 / 43.0 respectively, and collision energies are 17 eV, 7 eV, 3 eV respectively; quantitative ion pair of deuterated ethylene oxide - D4 is 48.0 / 30.0, collision energy is 5 eV, qualitative ion pair is 48.0 / 16.0, and collision energy is 40 eV.

[0063] Step 5, use Agilent MassHunter data processing software to analyze the data collected by mass spectrometry. The results of the pepper extract sample and the spike recovery analysis are shown in Table 2.

[0064] Table 2 Detection results of Example 1

[0065]

[0066] As can be seen from Table 2, the spike recovery rate of ethylene oxide in the pepper extract is 103.0%, within the range of 97.6% - 105.0%, and the relative standard deviation is 4.52%, within the range of 2.41% - 6.64%, meeting the requirements of GB / T27417 - 2017.

[0067] At the same time, export the chromatogram, and obtain according to the ordinate being the peak area and the abscissa being the acquisition time Figure 1 and Figure 2 .

[0068] As Figure 1 shown, there are no interfering peaks near the retention time (9.557 min) of ethylene oxide in the pepper extract sample.

[0069] As Figure 2 shown, there are no interfering peaks near the retention time (9.557 min) of deuterated internal standard ethylene oxide - D4 in the pepper extract sample.

[0070] Example 2

[0071] A detection and analysis method for ethylene oxide, comprising the following steps:

[0072] Step 1: Weigh 4 g of 2 chili extracts respectively into 50-mL centrifuge tubes for parallel detection; simultaneously, weigh 4 g of 2 chili extracts respectively into 50-mL centrifuge tubes for spiked recovery experiment at 0.02 mg / kg (add 0.008 mL of 10 mg / L ethylene oxide standard solution), and conduct 2 parallel detections for each spiked level; simultaneously, prepare a 50-mL centrifuge tube without weighing samples for full-course blank detection; add deuterated internal standard ethylene oxide-D4 (spiked concentration 2 mg / L, spiked volume 0.1 mL) to the above 5 50-mL centrifuge tubes respectively, and then add 20 mL of water / methanol / dimethyl sulfoxide (volume ratio 1:2:7) mixed solvent (previously placed in an 8 °C refrigerator for 2 h) to dissolve the samples to obtain chili extract sample solutions.

[0073] Step 2: After vortexing the 5 chili extract sample solutions for 30 s, add 100 mg of N-propylethylenediamine, 100 mg of silica-bonded octadecyl microspheres, and 100 mg of graphitized carbon black purification materials respectively, vortex for 30 s, and centrifuge at 10,000 r / min for 5 min under the condition of 4 °C to obtain the supernatant.

[0074] Step 3: Weigh 5 mL of the supernatant obtained by centrifugation above into 20-mL solid-phase microextraction vials respectively, add 1 g of sodium chloride respectively, tighten the vial caps, and vortex thoroughly to obtain the test solution.

[0075] Step 4: Use a gas chromatography-tandem mass spectrometry instrument (equipped with a CTC automatic solid-phase microextraction injection device) to extract and detect the prepared test solution; the specific instrument conditions are as follows:

[0076] (a) CTC conditions: Agilent SPME Arrow carbon WR / PDMS, 1.10 mm outer diameter, 120 μm stationary phase thickness, the injector is SPME-STD-V7.3; heating oven temperature: 80 °C; heating time: 30 min; SPME fiber aging temperature: 270 °C; aging time: 5 min.

[0077] (b) Use a programmed temperature large-volume injection port: Programmed temperature conditions: initial temperature 80 °C, hold for 0.25 min, and increase the temperature to 220 °C at a rate of 900 °C / min; split ratio: 3:1.

[0078] (c) Chromatographic column: DB-624UI, column length 60 m, inner diameter 0.25 mm, film thickness 1.40 μm; Programmed temperature conditions: initial temperature 40 °C, hold for 5 min, increase the temperature to 220 °C at a rate of 25 °C / min, hold for 3 min, and increase the temperature to 240 °C at a rate of 20 °C / min, hold for 5 min.

[0079] (d) Mass spectrometry conditions: EI source, electron energy of 70 eV, ion source temperature: 230 °C, transfer line temperature: 280 °C, solvent delay: 7.5 min, quantitative ion pair of ethylene oxide: 44.0 / 29.0, collision energy: 5 eV, qualitative ion pairs: 44.0 / 15.0, 44.0 / 42.0, 44.0 / 43.0, collision energies: 17 eV, 7 eV, 3 eV respectively; quantitative ion pair of deuterated ethylene oxide-D4: 48.0 / 30.0, collision energy: 5 eV, qualitative ion pair: 48.0 / 16.0, collision energy: 40 eV.

[0080] Step 5: Use Agilent MassHunter data processing software to analyze the data collected by mass spectrometry. The results of the chili extract sample and the spike recovery analysis are shown in Table 3.

[0081] Table 3 Detection results of Example 2

[0082]

[0083] As can be seen from Table 3, the spike recovery rate of ethylene oxide in the chili extract is 99.0%, within the range of 97.6% - 105.0%, and the relative standard deviation is 3.87%, within the range of 2.41% - 6.64%, meeting the requirements of GB / T 27417 - 2017.

[0084] Example 3

[0085] A method for the detection and analysis of ethylene oxide, comprising the following steps:

[0086] Step 1: Weigh 4.5 g of 2 chili extracts into 50 mL centrifuge tubes for parallel detection; at the same time, weigh 4.5 g of 2 chili extracts into 50 mL centrifuge tubes for a spike recovery experiment at 0.05 mg / kg (add 0.0225 mL of 10 mg / L ethylene oxide standard solution), and conduct 2 parallel detections for each spike level; at the same time, prepare a 50 mL centrifuge tube without weighing the sample for full-process blank detection. Add deuterated internal standard ethylene oxide-D4 (spike concentration 2 mg / L, spike volume 0.075 mL) to the above 5 50 mL centrifuge tubes, and then add 22.5 mL of water / methanol / dimethyl sulfoxide (volume ratio 1:2:7) mixed solvent (previously placed in a 6 °C refrigerator for 2 h) to dissolve the sample to obtain chili extract sample solutions.

[0087] Step 2: After vortexing the 5 chili extract sample solutions for 30 s, add 115 mg of N-propylethylenediamine, 115 mg of silica-bonded octadecyl microspheres, and 115 mg of graphitized carbon black purification materials respectively, vortex for 30 s, and centrifuge at a freezing centrifugation speed of 10000 r / min for 5 min at 4 °C to obtain the supernatant.

[0088] Step 3: Weigh 5 mL of the supernatant obtained from the above centrifugation into a 20 mL solid-phase microextraction vial, add 1 g of sodium chloride respectively, tighten the vial cap, and vortex thoroughly to obtain the test solution.

[0089] Step 4: Use a gas chromatography-tandem mass spectrometry (equipped with a CTC automatic solid-phase microextraction injection device) to extract and detect the prepared test solution; the specific instrument conditions are as follows:

[0090] (a) CTC conditions: Agilent SPME Arrow carbon WR / PDMS, 1.10 mm outer diameter, 120 μm stationary phase thickness, the injector is SPME-STD-V7.3; heating oven temperature: 80 °C; heating time: 30 min; SPME fiber aging temperature: 270 °C; aging time: 5 min.

[0091] (b) Use a programmed temperature large-volume injection port: Programmed temperature conditions: initial temperature 80 °C, hold for 0.25 min, ramp to 220 °C at 900 °C / min; split ratio: 3:1.

[0092] (c) Chromatographic column: DB-624UI, column length 60 m, inner diameter 0.25 mm, film thickness 1.40 μm; Programmed temperature conditions: initial temperature 40 °C, hold for 5 min, ramp to 220 °C at 25 °C / min, hold for 3 min, then ramp to 240 °C at 20 °C / min, hold for 5 min.

[0093] (d) Mass spectrometry conditions: EI source, electron energy 70 eV, ion source temperature: 230 °C, transfer line temperature 280 °C, solvent delay 7.5 min, the quantitative ion pair of ethylene oxide is 44.0 / 29.0, collision energy is 5 eV, the qualitative ion pairs are 44.0 / 15.0, 44.0 / 42.0, 44.0 / 43.0 respectively, and the collision energies are 17 eV, 7 eV, 3 eV respectively; the quantitative ion pair of deuterated ethylene oxide-D4 is 48.0 / 30.0, collision energy is 5 eV, the qualitative ion pair is 48.0 / 16.0, collision energy is 40 eV.

[0094] Step 5: Use Agilent MassHunter data processing software to analyze the data collected by mass spectrometry. The results of the chili extract sample and the spike recovery analysis are shown in Table 4.

[0095] Table 4 Detection results of Example 3

[0096]

[0097] As can be seen from Table 4, the spike recovery rate of ethylene oxide in the chili extract is 99.4%, within the range of 97.6% to 105.0%, and the relative standard deviation is 5.28%, within the range of 2.41% to 6.64%, meeting the requirements of GB / T 27417-2017.

[0098] In addition, the upper and lower limits and interval values of the process parameters (such as weight, volume, temperature, time, etc.) of the present invention can all implement the present invention, and the embodiments are not listed one by one herein.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for detecting and analyzing ethylene oxide, characterized in that It includes the following steps: Step 1: Weigh the sample to be tested, add deuterated internal standard ethylene oxide-D4, and dissolve the sample with a low-temperature mixed solvent to obtain a sample solution. Step 2: After mixing the sample solution, add purification materials for purification, mix well and centrifuge to obtain a supernatant. Step 3: Take a part of the supernatant and place it in a solid-phase microextraction vial, add sodium chloride, and mix well to obtain a solution to be tested. Step 4: Place the solid-phase microextraction vial containing the solution to be tested on a gas chromatography-tandem mass spectrometry instrument equipped with a CTC automatic solid-phase microextraction injection device to extract and detect the prepared solution to be tested. Step 5: Use Agilent MassHunter data processing software to analyze the data collected by the mass spectrometer.

2. The detection and analysis method of ethylene oxide according to claim 1, characterized in that In Step 1, the sample to be tested is a fat-soluble plant extract sample; the fat-soluble plant extract includes but is not limited to chili extract, tomato extract, marigold extract, and Chinese prickly ash extract.

3. The detection and analysis method of ethylene oxide according to claim 1, characterized in that In Step 1, the weighed amount of the sample to be tested is 4 - 5 g, and it is placed in a 50 mL centrifuge tube.

4. The detection and analysis method of ethylene oxide according to claim 1, characterized in that, In Step 1, the spiked concentration of the deuterated internal standard ethylene oxide-D4 is 2 mg / L, and the spiked volume is 0.05 - 0.1 mL.

5. The detection and analysis method of ethylene oxide according to claim 1, characterized in that, In Step 1, the low-temperature mixed solvent is a mixed solution of water, methanol, and dimethyl sulfoxide that has been placed in a refrigerator at 4 - 8 °C for at least 2 h; the volume ratio of water:methanol:dimethyl sulfoxide in the mixed solution is 1:2:7; the addition amount of the low-temperature mixed solvent is 20 - 25 mL.

6. The detection and analysis method of ethylene oxide according to claim 1, wherein In Step 2, the specific operation is as follows: After vortexing the sample solution for 30 s, add purification materials and vortex for another 30 s, and then perform freeze centrifugation at a centrifugation speed of 10000 r / min for 5 min at 4 °C.

7. The detection and analysis method of ethylene oxide according to claim 6, characterized in that, The purification materials include N-propylethylenediamine, silica-bonded octadecyl microspheres, and graphitized carbon black. The addition amount of N-propylethylenediamine is 100 - 125 mg, the addition amount of silica-bonded octadecyl microspheres is 100 - 125 mg, and the addition amount of graphitized carbon black is 100 - 125 mg.

8. The detection and analysis method of ethylene oxide according to claim 1, characterized in that, In Step 3, it specifically includes: Pipette 5 mL of the supernatant into a 20 mL solid-phase microextraction vial, add 1 g of sodium chloride, tighten the bottle cap, and vortex well to obtain a solution to be tested.

9. The detection and analysis method of ethylene oxide according to claim 1, characterized in that, In Step 4, the specific instrument conditions of the gas chromatography-tandem mass spectrometry instrument equipped with a CTC automatic solid-phase microextraction injection device are as follows: (a) CTC conditions: Agilent SPME Arrow carbon WR / PDMS, 1.10 mm outer diameter, 120 µm stationary phase thickness, injector is SPME-STD-V7.3; heating oven temperature: 80 °C; heating time: 30 min; SPME fiber aging temperature: 270 °C; aging time: 5 min. (b) Use a programmed temperature large volume injection port: Programmed temperature conditions: Initial temperature 80 °C, hold for 0.25 min, and increase the temperature to 220 °C at a rate of 900 °C / min; split ratio: 3:

1. (c) Chromatographic column: DB-624 UI, column length 60 m, inner diameter 0.25 mm, film thickness 1.40 μm; Program temperature conditions: initial temperature 40 °C, hold for 5 min, increase temperature to 220 °C at a rate of 25 °C / min, hold for 3 min, increase temperature to 240 °C at a rate of 20 °C / min, hold for 5 min; (d) Mass spectrometry conditions: EI source, electron energy 70 eV, ion source temperature: 230 °C, transfer line temperature 280 °C, solvent delay 7.5 min, quantitative ion pair of ethylene oxide is 44.0 / 29.0, collision energy is 5 eV, qualitative ion pairs are 44.0 / 15.0, 44.0 / 42.0, 44.0 / 43.0 respectively, collision energies are 17 eV, 7 eV, 3 eV respectively; Quantitative ion pair of deuterated ethylene oxide-D4 is 48.0 / 30.0, collision energy is 5 eV, qualitative ion pair is 48.0 / 16.0, collision energy is 40 eV.

10. The detection and analysis method of ethylene oxide according to claim 1, characterized in that, During the detection and analysis, the detection and analysis of two samples need to be done in parallel, and the average value is taken as the detection result; At the same time, two parallel detections are carried out for 1 spiking level; At the same time, 1 blank detection also needs to be done.

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