Method for detecting diphenyl pentene in water and fish body based on LC-MSMS

Abstract

The invention discloses a method for detecting diphenyl pentene in water and a fish body based on LC-MSMS (liquid chromatography-mass spectrometry). The method comprises the following steps: 1, respectively determining different detection conditions according to the detected water and the fish body by adopting LC-MSMS; 2, preparing a working solution of a detected object; 3, carrying out sample introduction test on a blank solvent, a blank matrix sample and the standard working solution with the lowest-grade concentration by using the established LC-MS / MS analysis method; 4, testing the recovery rate and repeatability; 5, detection limit and quantification limit; 6, analyzing experimental results including specificity, linear range and correlation, recovery rate and repeatability, and detection limit and quantitation limit; compared with the prior art, the method has the advantages that in an analysis method confirmation test, the target object can be qualitatively and quantitatively determined through retention time and qualitative and quantitative ion pairs, the interference phenomenon of other impurities does not exist, and the method has good selectivity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of detection, in particular to a method for detecting diphenylpentene in water and fish bodies based on LC-MSMS. BACKGROUND

[0002] LC-MS / MS refers to liquid chromatography-tandem mass spectrometry, which is an analysis method further developed on the basis of LC-MS. Compared with LC-MS, it adds a second mass spectrometer detector, which can provide more in-depth chemical information. This technology is not only used for qualitative and quantitative analysis of compounds, but also commonly used in advanced analysis fields such as drug metabolism research, isotope analysis, and small molecule compound structure analysis. It is favored for its high sensitivity, high resolution, and high dynamic range. The present application tests the detection method of diphenylpentene in the environment by LC-MS / MS.

[0003] The information disclosed in this BACKGROUND section is only intended to increase an understanding of the general context in which the application can be practiced. It is not admitted that any of the information provided in this section constitutes prior art. SUMMARY

[0004] The technical problem to be solved by the present application is to overcome the above technical defects, and to provide a method for detecting diphenylpentene in water and fish bodies based on LC-MSMS. In the analysis method confirmation test, the qualitative and quantitative ions can realize the qualitative and quantitative analysis of the target substance, there is no interference phenomenon of other impurities, and the method has good selectivity.

[0005] In order to solve the above problems, the technical scheme of the present application is a method for detecting diphenylpentene in water and fish bodies based on LC-MSMS, comprising the following steps:

[0006] Step one, using ultra-high performance liquid chromatography-triple quadrupole mass spectrometer, respectively according to the detection of water and fish bodies to determine different detection conditions;

[0007] Step two, the configuration of the detected substance working solution, including the preparation of diphenylpentene stock solution and the preparation of diphenylpentene working solution, using dilution solvent to dilute the diphenylpentene working solution to obtain standard working solution, and the standard working solution is configured with a series of standard working solutions with different concentrations;

[0008] Step three, using the established LC-MS / MS analysis method to test the blank solvent, blank matrix sample and standard working solution with the lowest concentration;

[0009] Step 4: Recovery and repeatability tests. One blank matrix sample and two additive concentrations were set up in the test water and fish respectively for recovery and repeatability tests. Five replicates were performed for each concentration. The precision of the analytical method was reflected by repeatability, expressed as relative standard deviation (RSD). Repeatability was analyzed by adding the recovery test solution and calculating the RSD of five replicates for each concentration.

[0010] Step 5: Limit of Detection and Limit of Quantification. The limit of detection (LOD) of the method is set to 3 times the baseline noise, that is, the concentration of the target analyte at a signal-to-noise ratio of 3. The limit of quantification (LOQ) of the method is set to 10 times the baseline noise, that is, the concentration of the target analyte at a signal-to-noise ratio of 10.

[0011] Step 6: Analysis of experimental results, including specificity, linear range and correlation, recovery and repeatability, limit of detection and limit of quantitation.

[0012] Preferably, in step one, the instrument operating conditions for determining the concentration of the test substance in the test water are as follows: detector: MSD; column: EclipsePlus C1850 mm × 2.1 mm (id), 1.8 μm, SN: USDAY93369; flow rate: 0.300 mL / min; injection volume: 5.00 μL; column temperature: 40.0℃; mobile phase A: 0.1% formic acid aqueous solution; mobile phase B: methanol; run time: 6.00 min; retention time: approximately 3.0 min;

[0013] The instrument operating conditions for determining the concentration of the test substance in fish were as follows: detector: MSD; column: EclipsePlus C1850 mm × 2.1 mm (id), 1.8 μm, SN: USDAY93369; flow rate: 0.300 mL / min; injection volume: 10.00 μL; column temperature: 40.0℃; mobile phase A: 0.1% formic acid aqueous solution; mobile phase B: methanol; run time: 10.00 min; retention time: approximately 5.5 min.

[0014] Preferably, in step two, the diluent is 50% methanol-water or 50% acetonitrile-methanol.

[0015] Preferably, in step three, the series of standard working solutions have 7 calibration points for the standard curve, with a linear range of 0.100-10.0 μg / L. The established LC-MS / MS analytical method is used for determination, with two samples collected for each concentration. The concentration of diphenylpentene is used as the abscissa, and the average peak area is used as the ordinate. A linear regression equation is used to fit the standard curve.

[0016] Preferably, in step four, the recovery rate is calculated using the following formula:

[0017]

[0018] Where R is the recovery rate, C d C represents the measured concentration of the target analyte. a The actual concentration of the target substance added;

[0019] The formula for calculating standard deviation is:

[0020]

[0021] Where S is the standard deviation, x i Let i be the recovery rate obtained from the i-th measurement. is the average recovery rate, and N is the number of recovery rates included in the calculation;

[0022] The formula for calculating the relative standard deviation is:

[0023]

[0024] RSD stands for relative standard deviation.

[0025] Preferably, in step five, the formula for calculating the detection limit of the method is:

[0026]

[0027] Where LOD is the limit of detection; C is the actual concentration added in the low concentration range; R S / N The signal-to-noise ratio corresponds to the concentration.

[0028] The formula for calculating the limit of quantitation of a method is:

[0029]

[0030] Where LOQ is the limit of quantitation; C is the theoretical concentration for recovery at low concentration levels; R S / N —Concentration corresponds to signal-to-noise ratio.

[0031] The advantages of this invention compared to existing technologies are:

[0032] 1. In the analytical method confirmation test, the present invention can achieve qualitative and quantitative analysis of the target analyte by means of retention time and qualitative and quantitative ion pairs, without interference from other impurities, and the method has good selectivity.

[0033] 2. Recovery and repeatability of the present invention: In test water, the average recovery rate at an actual addition concentration of 0.500 μg / L was 93.7%, with an RSD of 0.718%; the average recovery rate at an actual addition concentration of 35.0 μg / L was 96.1%, with an RSD of 0.745%. In fish, the average recovery rate at a theoretical addition concentration of 2.00 μg / kg was 61.5%, with an RSD of 2.16%; the average recovery rate at a theoretical addition concentration of 100 μg / kg was 90.6%, with an RSD of 7.16%; the average recovery rate at a theoretical addition concentration of 20.0 mg / kg was 105%, with an RSD of 0.797%; and the average recovery rate at a theoretical addition concentration of 250 mg / kg was 100%, with an RSD of 2.33%.

[0034] 3. In this invention, the limit of quantification (LOQ) of diphenylpentene in test water is 0.130 μg / L and the limit of detection (LOD) is 0.0391 μg / L; the limit of quantification (LOQ) in fish is 0.719 μg / kg and the LOD is 0.222 μg / kg. Attached Figure Description

[0035] Figure 1 This is the standard working curve of the present invention (50% methanol test water).

[0036] Figure 2 This is a typical chromatogram of the standard working solution of the present invention (50% methanol test water 0.100 μg / L).

[0037] Figure 3 This is a typical chromatogram of the standard working solution of the present invention (50% methanol test water 10.0 μg / L).

[0038] Figure 4 This is a typical spectrum of the blank solvent of this invention (50% methanol test water).

[0039] Figure 5 This is a typical spectrum of the blank matrix sample (test water) of the present invention.

[0040] Figure 6 This is a typical chromatogram of the recovery test sample added to the test water of the present invention (actual added concentration 0.500 μg / L).

[0041] Figure 7 This is a typical chromatogram of the recovery test sample added to the test water of this invention (actual added concentration 35.0 μg / L).

[0042] Figure 8 This is the standard working curve of the present invention (50% acetonitrile methanol).

[0043] Figure 9 This is a typical chromatogram of the standard working solution of this invention (50% acetonitrile methanol 0.100 μg / L).

[0044] Figure 10 This is a typical chromatogram of the standard working solution of this invention (50% acetonitrile methanol 10.0 μg / L).

[0045] Figure 11 This is a typical spectrum of the blank solvent of this invention (50% acetonitrile methanol).

[0046] Figure 12 This is a typical spectrum of the blank matrix sample of the present invention (fish blank).

[0047] Figure 13 This is a typical spectrum of the recovery test sample added to the fish body according to the present invention (theoretical addition concentration 2.00 μg / kg).

[0048] Figure 14 This is a typical spectrum of the recovery test sample added to the fish body according to the present invention (theoretical addition concentration 100 μg / kg).

[0049] Figure 15 This is a typical spectrum of the recovery test sample added to the fish body according to the present invention (theoretical addition concentration 20.0 mg / kg).

[0050] Figure 16 This is a typical spectrum of the recovery test sample added to the fish body according to the present invention (theoretical addition concentration 250 mg / kg).

[0051] Figure 17 This is the signal-to-noise ratio spectrum of the standard working solution of this invention (50% methanol test water 0.100 μg / L).

[0052] Figure 18 This is the signal-to-noise ratio spectrum of the recovered test sample added to the test water of this invention (actual added concentration 0.500 μg / L).

[0053] Figure 19 This is the signal-to-noise ratio spectrum of the standard working solution of this invention (50% acetonitrile methanol 0.100 μg / L).

[0054] Figure 20 This is the signal-to-noise ratio spectrum of the recovered sample added to the fish body according to the present invention (theoretical addition concentration 2.00 μg / kg). Detailed Implementation

[0055] To make the content of this invention easier to understand, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings.

[0056] A method for detecting diphenylpentene in water and fish based on LC-MSMS includes the following steps:

[0057] Preparation of main instruments:

[0058] Ultra-high performance liquid chromatography-triple quadrupole mass spectrometry system, electronic balance, fully automated rapid sample grinder, medical centrifuge.

[0059] Main reagents:

[0060] Methanol: chromatographic grade; Acetonitrile: chromatographic grade; Formic acid: chromatographic grade; Sodium chloride: AR; Ultrapure water: resistivity 18.2 MΩ×cm; Test water: laboratory tap water filtered through PP cotton, granular activated carbon, compressed activated carbon and other filters to remove residual chlorine and insoluble particulate matter.

[0061] Operating conditions for the instrument used to determine the concentration of the test substance in the test water:

[0062] Detected substance: diphenylpentene

[0063] Instrument used: Agilent 1290-6495A

[0064] Detector: MSD

[0065] Column: Ecl ipsePlus C1850 mm × 2.1 mm (id), 1.8 μm, SN: USDAY93369; Flow rate: 0.300 mL / min

[0066] Injection volume: 5.00 μL

[0067] Column temperature: 40.0℃

[0068] Mobile phase A: 0.1% formic acid aqueous solution

[0069] Mobile phase B: Methanol

[0070] Runtime: 6.00 min

[0071] Retention time: Approximately 3.0 minutes

[0072] Table 1 Elution gradient (determination of test substance concentration in test water)

[0073]

[0074]

[0075] Ion source: AJS ESI

[0076] Drying gas: N2; Drying gas temperature: 250℃; Drying gas flow rate: 14L / min Sheath gas: N2; Sheath gas temperature: 250℃; Sheath gas flow rate: 11 L / min

[0077] Atomizer pressure: 35 psi; Nozzle voltage: 500 V; Capillary voltage: 1500 V Acquisition Mode: MRM Mode

[0078] Scan range:

[0079] Table 2 Ion Collection Parameters (Determination of Test Substance Concentration in Test Water)

[0080] Note: Ions marked with "*" are quantitative ions.

[0081] Determination of the concentration of test substance in fish: Instrument operating conditions; Detected substance: diphenylpentene; Instrument used: Agilent 1290-6495A

[0082] Detector: MSD

[0083] Column: Ecl ipsePlus C1850 mm × 2.1 mm (id), 1.8 μm, SN: USDAY93369; Flow rate: 0.300 mL / min

[0084] Injection volume: 10.00 μL

[0085] Column temperature: 40.0℃

[0086] Mobile phase A: 0.1% formic acid aqueous solution; Mobile phase B: Methanol; Running time: 10.00 min

[0087] Retention time: Approximately 5.5 minutes

[0088] Table 3 Elution gradient (determination of test substance concentration in fish)

[0089]

[0090] Ion source: AJS ESI

[0091] Drying gas: N2; Drying gas temperature: 250℃; Drying gas flow rate: 14L / min Sheath gas: N2; Sheath gas temperature: 250℃; Sheath gas flow rate: 11 L / min Atomizer pressure: 35 psi; Nozzle voltage: 500 V; Capillary voltage: 1500 V Acquisition Mode: MRM Mode

[0092] Scan range:

[0093] Table 4 Ion Acquisition Parameters (Determination of Test Substance Concentration in Fish)

[0094]

[0095] Note: Ions marked with "*" are quantitative ions.

[0096] Preparation of working solution for test substance:

[0097] Preparation of diphenylpentene stock solution:

[0098] Table 5 Standard Stock Solution Preparation Record Sheet

[0099]

[0100] Preparation of diphenylpentene working solution:

[0101] Table 6 Working Solution Preparation Record Sheet

[0102]

[0103] Table 7 Standard Working Solution Preparation Record Sheet - 50% Methanol Test Water

[0104]

[0105] Note: This standard working solution is used for the determination of test substances in test water.

[0106] Table 8. Standard Working Solution Preparation Record Sheet - 50% Acetonitrile Methanol

[0107]

[0108] Note: This standard working solution is used for the determination of test substances in fish.

[0109] Methodological validation:

[0110] Exclusivity:

[0111] The established LC-MS / MS analytical method was used to test blank solvent (50% methanol test water), blank matrix sample (test water), and standard working solutions of the lowest concentration in Table 7.

[0112] The established LC-MS / MS analytical method was used to test blank solvent (50% acetonitrile methanol), blank matrix sample (fish blank), and standard working solution of the lowest concentration in Table 8.

[0113] Linearity and Range:

[0114] A series of standard working solutions were prepared according to Table 7. In a 50% methanol test water matrix, the standard curve was set with 7 calibration points, and its linear range was 0.100-10.0 μg / L. The established LC-MS / MS analytical method was used for determination. Two samples were collected for each concentration. The concentration of diphenylpentene was used as the abscissa and the average peak area was used as the ordinate. The standard curve was fitted by a linear regression equation.

[0115] A series of standard working solutions were prepared according to Table 8. In a 50% acetonitrile-methanol matrix, the standard curve was set with 7 calibration points, and its linear range was 0.100-10.0 μg / L. The established LC-MS / MS analytical method was used for determination. Two samples were collected for each concentration. The concentration of diphenylpentene was used as the abscissa and the average peak area was used as the ordinate. The standard curve was fitted by a linear regression equation.

[0116] Recovery rate and repeatability tests:

[0117] One blank matrix sample (test water) and two additive concentrations were set up in the test water for recovery and repeatability tests. Five replicates were performed for each concentration.

[0118] One blank matrix sample (fish blank) and four different additive concentrations were set up in the fish for recovery and repeatability tests. Five replicates were performed for each concentration.

[0119] The precision of an analytical method is reflected in its repeatability, expressed as the relative standard deviation (RSD).

[0120] Repeatability was analyzed by adding the recovery test solution and calculating the RSD of five parallel samples for each concentration.

[0121] The actual concentration of diphenylpentene in the low-concentration recovery test sample in the test water was 0.500 μg / L, and the actual concentration in the high-concentration recovery test sample was 35.0 μg / L. The preparation process is shown in Table 9. After pretreatment, tests were conducted according to the instrument operating conditions, and the recovery rate and relative standard deviation (RSD) of the recovery rate were calculated using the formula.

[0122] The theoretical concentrations of diphenylpentene added to fish samples for recovery were 2.00 μg / kg, 100 μg / kg, 20.0 mg / kg, and 250 mg / kg, respectively. The preparation process is shown in Table 10. After pretreatment, tests were conducted according to the instrument operating conditions, and the recovery rate and relative standard deviation (RSD) of the recovery rate were calculated using the formula.

[0123] The formula for calculating the recovery rate is:

[0124]

[0125] Where R is the recovery rate, C d C represents the measured concentration of the target analyte. a The actual concentration of the target substance added.

[0126] The formula for calculating standard deviation is:

[0127]

[0128] Where S is the standard deviation, x iLet i be the recovery rate obtained from the i-th measurement. is the average recovery rate, and N is the number of recovery rates included in the calculation.

[0129] The formula for calculating the relative standard deviation is:

[0130]

[0131] RSD stands for relative standard deviation.

[0132] Table 9. Preparation of Samples for Adding Recycling to Test Water

[0133]

[0134] Pretreatment process: Take blank matrix sample (test water, S-KB) and test water respectively, add recovered test sample and filter through 0.45μm PTFE membrane. Take the filtrate of S-KB and HSL-SL-1 to 5 and dilute it 2 times with methanol; take the filtrate of HSL-SH-1 to 5 and dilute it 5 times with 50% methanol test water.

[0135] Table 10. Preparation of Samples for Adding Recovered Substances to Fish Carcasses

[0136]

[0137] Note: Theoretical addition concentration = working solution concentration × addition volume / fish body weight (fish body weight is calculated as 2g); Actual addition concentration = working solution concentration × addition volume / actual fish body weight; the fish body weight added in the table is the actual fish body weight added.

[0138] Preparation of the fish sample for recovery testing: Collect fish samples, rinse the fish with test water, euthanize the fish, dry the surface water, and weigh the fish to obtain 75.14g of fish sample. Place the fish sample in a 50mL round-bottom plastic tube, add stainless steel grinding beads, and place it in a fully automatic rapid sample grinder. Grind at a frequency of 70Hz, running for 120s followed by a 10s pause, for 4 cycles. After grinding, remove the sample to prepare a fish paste sample for the fish recovery testing. Weigh approximately 2g of fish paste sample into a 15mL centrifuge tube, add the working solution according to Table 10, mix well, and prepare the fish recovery testing sample.

[0139] Pretreatment process: Add 10.00 mL of 0.1% formic acid acetonitrile solution, 1.00 g of sodium chloride, 1 mL of UP water, and 3 stainless steel grinding beads to the blank matrix sample (fish blank, Y-KB) and the fish recovery test sample, respectively. Place them in a fully automated rapid sample grinder and grind at a frequency of 70 Hz. Repeat the process 4 times, running for 120 s followed by a 10 s pause. After grinding, remove the sample. Centrifuge at 5000 rpm for 5 min at 0℃. Take approximately 1.5 mL of the supernatant and transfer it to a 2 mL sample vial. Add 60 mg of C18 powder and 60 mg of PAS powder, mix well, and allow to separate into layers. Dilute the supernatant of Y-KB and HSL-YL-1~5 with methanol by 2 times.

[0140] The supernatant of HSL-Y-M1-1 to 5 was diluted 50 times with 50% acetonitrile methanol; the supernatant of HSL-Y-M2-1 to 5 was diluted 1000 times with 50% acetonitrile methanol; the supernatant of HSL-YH-1 to 5 was diluted 10000 times with 50% acetonitrile methanol.

[0141] Limit of detection and limit of quantitation:

[0142] The method's limit of detection (LOD) is set at three times the baseline noise, i.e., the concentration of the target analyte at a signal-to-noise ratio of 3. The method's LOD is calculated using the formula.

[0143] The formula for calculating the detection limit of the method is:

[0144]

[0145] Where LOD is the limit of detection; C is the actual concentration added in the low concentration range; R S / N This represents the signal-to-noise ratio corresponding to the concentration.

[0146] The method's limit of quantitation (LOQ) is set at 10 times the baseline noise, i.e., the concentration of the target analyte at a signal-to-noise ratio of 10. The method's LOQ is calculated using the formula.

[0147] The formula for calculating the limit of quantitation of a method is:

[0148]

[0149] Where LOQ is the limit of quantitation; C is the theoretical concentration for recovery at low concentration levels; R S / N —Concentration corresponds to signal-to-noise ratio.

[0150] Experimental results:

[0151] Exclusivity:

[0152] In the analytical method validation test (determination of the concentration of the test substance in the test water), the retention time of diphenylpentene was approximately 3.0 min. Qualitative and quantitative analysis of the target analyte was achieved through retention time and qualitative / quantitative ion chelation, with no interference from other impurities, demonstrating good selectivity. See appendix for details. Figure 2 -Appendix Figure 5 .

[0153] In the analytical method validation test (determination of the concentration of the test substance in fish), the retention time of diphenylpentene was approximately 5.5 min. Qualitative and quantitative analysis of the target analyte was achieved through retention time and qualitative / quantitative ion juxtaposition. No other impurities were observed to interfere, demonstrating good selectivity of the method. See appendix for details. Figure 9 -Appendix Figure 12 .

[0154] Linear range and correlation:

[0155] In 50% methanol test water, the linear range of diphenylpentene was 0.100 μg / L–10.0 μg / L, with a linear equation of y = 21372.850x - 905.298, and a linearity R0. 2 The value is 0.998. The measurement results are shown in Appendix 1 and Appendix 2. Figure 1 .

[0156] In 50% acetonitrile methanol, the linear range of diphenylpentene is 0.100 μg / L–10.0 μg / L, and the linear equation is y = 42779.789x - 1491.107, with a linearity R0. 2 The value is 0.995. The measurement results are shown in Appendix 2 and Appendix 3. Figure 8 .

[0157] Recovery rate and repeatability:

[0158] In the test water, the average recovery rate was 93.7% with an RSD of 0.718% at an actual added concentration of 0.500 μg / L; the average recovery rate was 96.1% with an RSD of 0.745% at an actual added concentration of 35.0 μg / L. The results are shown in Appendix Table 3. Figure 6 and attached Figure 7 .

[0159] In fish, the average recovery rate at a theoretical concentration of 2.00 μg / kg was 61.5%, with an RSD of 2.16%; the average recovery rate at a theoretical concentration of 100 μg / kg was 90.6%, with an RSD of 7.16%; the average recovery rate at a theoretical concentration of 20.0 mg / kg was 105%, with an RSD of 0.797%; and the average recovery rate at a theoretical concentration of 250 mg / kg was 100%, with an RSD of 2.33%. The results are shown in Appendix Table 4. Figure 13 -Appendix Figure 16 .

[0160] Limit of detection and limit of quantitation:

[0161] The limit of quantitation (LOQ) of diphenylpentene in test water was 0.130 μg / L, and the limit of detection (LOD) was 0.0391 μg / L; in fish, the LQ was 0.719 μg / kg, and the LOD was 0.222 μg / kg. The results are shown in Appendix Tables 5 and 6.

[0162] Experimental results statistics:

[0163] Appendix 1 Standard Curve Test Results - 50% Methanol Test Water

[0164]

[0165] Appendix 2 Standard Curve Test Results - 50% Acetonitrile Methanol

[0166]

[0167]

[0168] Appendix 3 Results of the recovery rate test in the test water

[0169]

[0170] Appendix Table 4 Results of the recovery rate test in fish

[0171]

[0172]

[0173] Appendix 5: Limits of Detection and Limits of Quantification (LOQ) for the Analytical Methods (Test Water)

[0174]

[0175] Appendix 6: Limits of Detection and Limits of Quantification (LOQ) for the Analytical Methods (Fish)

[0176]

[0177] Appendix 7 Storage Stability Test Results—Test Water (Non-GLP)

[0178]

[0179] Note: After pretreatment, the test solution should be stored in a refrigerator at 0–5°C.

[0180] Appendix 8: Storage Stability Test Results—Fish (Non-GLP)

[0181]

[0182] Note: After pretreatment, the test solution should be stored in a refrigerator at 0–5°C.

[0183] The present invention and its embodiments have been described above, and such description is not restrictive. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. A method for detecting diphenylpentene in water and fish based on LC-MSMS, characterized in that, Includes the following steps: Step 1: Using an ultra-high performance liquid chromatography-triple quadrupole mass spectrometer, different detection conditions were determined for the water and fish being tested, respectively. Step 2: Preparation of the working solution for the analyte, including the preparation of diphenylpentene stock solution and diphenylpentene working solution. The diphenylpentene working solution is diluted with a diluent to obtain a standard working solution. A series of standard working solutions with different concentrations are prepared. Step 3: Use the established LC-MS / MS analysis method to test blank solvent, blank matrix sample and standard working solution of the lowest concentration. Step 4: Recovery and repeatability tests. One blank matrix sample and two additive concentrations were set up in the test water and fish respectively for recovery and repeatability tests. Five replicates were performed for each concentration. The precision of the analytical method was reflected by repeatability, expressed as relative standard deviation (RSD). Repeatability was analyzed by adding the recovery test solution and calculating the RSD of five replicates for each concentration. Step 5: Limit of Detection and Limit of Quantification. The limit of detection (LOD) of the method is set to 3 times the baseline noise, that is, the concentration of the target analyte at a signal-to-noise ratio of 3. The limit of quantification (LOQ) of the method is set to 10 times the baseline noise, that is, the concentration of the target analyte at a signal-to-noise ratio of 10. Step 6: Analysis of experimental results, including specificity, linear range and correlation, recovery and repeatability, limit of detection and limit of quantitation.

2. The method for detecting diphenylpentene in water and fish based on LC-MSMS according to claim 1, characterized in that: In step one, the instrument operating conditions for determining the concentration of the test substance in the test water are as follows: detector: MSD; Chromatographic column: EclipsePlus C1850 mm × 2.1 mm (id), 1.8 μm, SN: USDAY93369; Flow rate: 0.300 mL / min; Injection volume: 5.00 μL; Column temperature: 40.0℃; Mobile phase A: 0.1% formic acid aqueous solution; Mobile phase B: methanol; Run time: 6.00 min; Retention time: approximately 3.0 min; The instrument operating conditions for determining the concentration of the test substance in fish are as follows: Detector: MSD; Chromatographic column: EclipsePlus C18 50mm × 2.1mm (id), 1.8μm, SN: USDAY93369; Flow rate: 0.300mL / min; Injection volume: 10.00μL; Column temperature: 40.0℃; Mobile phase A: 0.1% formic acid aqueous solution; Mobile phase B: methanol; Run time: 10.00min; Retention time: approximately 5.5min.

3. The method for detecting diphenylpentene in water and fish based on LC-MSMS according to claim 1, characterized in that: In step two, the diluent is either 50% methanol-water or 50% acetonitrile-methanol.

4. The method for detecting diphenylpentene in water and fish based on LC-MSMS according to claim 1, characterized in that: In step three, the series of standard working solutions, the standard curve is set with 7 calibration points, and the linear range is 0.100-10.0 μg / L; the established LC-MS / MS analysis method is used for determination, and two samples are collected for each concentration. The concentration of diphenylpentene is used as the abscissa and the average peak area is used as the ordinate. The standard curve is fitted by a linear regression equation.

5. The method for detecting diphenylpentene in water and fish based on LC-MSMS according to claim 1, characterized in that: In step four, the recovery rate is calculated using the following formula: Where R is the recovery rate, C d C represents the measured concentration of the target analyte. a The actual concentration of the target substance added; The formula for calculating standard deviation is: Where S is the standard deviation, x i Let i be the recovery rate obtained from the i-th measurement. is the average recovery rate, and N is the number of recovery rates included in the calculation; The formula for calculating the relative standard deviation is: RSD stands for relative standard deviation.

6. The method for detecting diphenylpentene in water and fish based on LC-MSMS according to claim 1, characterized in that: In step five, the formula for calculating the detection limit of the method is: Where LOD is the limit of detection; C is the actual concentration added in the low concentration range; R S / N The signal-to-noise ratio corresponds to the concentration. The formula for calculating the limit of quantitation of a method is: Where LOQ is the limit of quantitation; C is the theoretical concentration for recovery at low concentration levels; R S / N —Concentration corresponds to signal-to-noise ratio.

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