Ultrahigh-sensitivity detection method for amphetamine substances in sewage

Abstract

The invention relates to ultrahigh-sensitivity detection of amphetamine substances, and particularly discloses an ultrahigh-sensitivity detection method of amphetamine substances in sewage, which makes full use of the advantages of capillary electrophoresis field amplification on-line enrichment and the advantages of high sensitivity and high specificity of tandem mass spectrometry. The invention provides a method for determining the content of the amphetamine substances in the sewage through a capillary electrophoresis field amplification enrichment-mass spectrometry (FASI-CE-MS / MS), and ultrahigh-sensitivity detection of the amphetamine substances in the sewage is realized. According to the method, the FASI-CE method is specifically developed, CE-MS / MS interface parameters and MS / MS parameters of amphetamine substances are optimized, the detection sensitivity and reliability of the amphetamine substances are remarkably improved, the detection limit reaches 0.1 ng / L, and the method is particularly suitable for ultrahigh-sensitivity detection of trace amphetamine substances in a water sample on a large scale.

Description

Technical Field

[0001] The present invention relates to the technical field of substance detection, in particular to the detection of amphetamine substances, and in particular to an ultra-high sensitive detection method for amphetamine substances in sewage. Background Art

[0002] In the field of drug control, by monitoring trace amounts of amphetamines and their metabolites in sewage, information on the abuse trend, prevalence and geographical distribution of amphetamines can be provided, thereby understanding the use of amphetamines in the community and city. After being used by drug addicts, amphetamines will enter the urban drainage system through human metabolism. Using sewage epidemiology, that is, sewage analysis, to conduct qualitative and quantitative analysis of trace amounts of amphetamines and their metabolites in urban sewage, combined with sewage flow and the population of the area covered by the sewage treatment plant, it is possible to effectively obtain regional amphetamine abuse types, abuse quantities, abuse scale and other drug data. Although scholars still have doubts about the uncertainty of the sewage epidemiology back calculation process, scholars from various countries have reached a consensus on the chemical analysis step as the core data source.

[0003] At present, for the qualitative and quantitative analysis of amphetamines in urban sewage samples, online solid phase extraction technology is often used to enrich the samples, and then liquid chromatography-mass spectrometry is used for detection. However, although the existing technical solutions can accurately achieve the qualitative and quantitative detection of amphetamines in urban sewage, the solid phase extraction technology has cumbersome operation steps, long time consumption, poor repeatability, and high requirements for equipment and personnel quality, which limits the promotion and application of this method.

[0004] Capillary electrophoresis (CE) is an electrophoretic separation and analysis method that uses quartz capillaries as separation channels and high-voltage direct current electric fields as driving forces. It achieves separation based on the differences in mobility or distribution behavior between components in the sample. It has the characteristics of high efficiency, rapidity, trace volume, and multiple modes. With its unique online enrichment and separation capabilities, capillary electrophoresis can simplify the sample pretreatment process and improve efficiency. Especially when combined with mass spectrometry, it has shown great application potential in the analysis of trace substances. However, in the process of CE-MS / MS application experiments, it was found that the simple combination of capillary electrophoresis and mass spectrometry has the problem of low detection sensitivity, which seriously affects its large-scale application in the qualitative and quantitative analysis of amphetamines in urban sewage. Summary of the invention

[0005] The object of the present invention is to overcome the problem of low sensitivity of the detection result when the capillary electrophoresis method and mass spectrometry are used to detect the content of amphetamines in water, and a method for ultra-sensitive detection of amphetamines in sewage is proposed. The present invention makes full use of the advantages of capillary electrophoresis field amplification online enrichment and the advantages of tandem mass spectrometry with high sensitivity and high specificity, and proposes a method for measuring the content of amphetamines in sewage by capillary electrophoresis field amplification enrichment-mass spectrometry (FASI-CE-MS / MS), thereby realizing ultra-sensitive detection of amphetamines in sewage.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides an ultra-sensitive detection method for amphetamines in sewage, comprising: using capillary electrophoresis field amplification enrichment-mass spectrometry (FASI-CE-MS / MS) to determine the content of amphetamines in sewage;

[0007] Wherein, the amphetamine-type substance includes at least one of methamphetamine (MAMP), amphetamine (AMP), 3,4-methylenedioxymethamphetamine (MDMA), and 3,4-methylenedioxymethamphetamine (MDA);

[0008] The capillary electrophoresis field amplification enrichment parameters are: the buffer is 180-220mmol / L ammonium formate aqueous solution; the water plug length: 50mbar pressure water plug injection 6-10s; injection conditions: 30kV injection 20-30s; operating voltage: 18-22kV; operating time: 6-8min; auxiliary pressure: 80-120mbar;

[0009] The capillary electrophoresis field amplification enrichment-mass spectrometry method uses a coaxial sheath flow interface to connect the capillary electrophoresis instrument and the mass spectrometer; the sheath flow liquid is 8-12mmol / L ammonium formate aqueous solution, and the flow rate of the sheath flow liquid entering the ion source is controlled at 0.5μL / min;

[0010] The mass spectrometry parameters are: detection mode: multiple reaction monitoring (MRM), selecting 2 pairs of parent ion / daughter ion pairs as qualitative ion pairs; ion source parameters: positive ion mode; drying gas temperature is 90°C; drying gas flow rate is 9L / min; nebulizer is 40psi; sheath gas (nitrogen) temperature is 90°C; sheath gas flow rate is 7L / min; capillary voltage is 2100V; nozzle voltage is 600V; other mass spectrometry detection parameters of different amphetamine substances are shown in the following table:

[0011]

[0012] The invention discloses an ultra-high sensitive detection method for amphetamine substances in sewage. The method optimizes the type and concentration of a buffer solution and the type and concentration of a sheath fluid when the content of amphetamine substances is determined by a capillary electrophoresis field amplification enrichment-mass spectrometry method, and increases the auxiliary pressure during the capillary electrophoresis field amplification enrichment, thereby significantly improving the current stability and sensitivity when the capillary electrophoresis field amplification enrichment is performed on an amphetamine substance solution, thereby better realizing the enrichment and separation of amphetamine substances in a test solution, significantly improving the detection sensitivity of amphetamine substances, and achieving a detection limit of 0.1 ng / L. The method is particularly suitable for large-scale application in the detection of trace amphetamine substances in water samples.

[0013] Preferably, the capillary in the capillary electrophoresis field amplification enrichment is an uncoated fused silica capillary; the preferred capillary type has better current stability, better enrichment effect on amphetamines, and higher sensitivity; more preferably, the capillary has a length of 80-100 cm, an inner diameter of 50 μm, and an outer diameter of 365 μm; the preferred capillary size is not easy to break, and has a better enrichment effect on amphetamines.

[0014] Preferably, before performing capillary electrophoresis field amplification enrichment, the capillary is flushed with 0.8-1.2mol / L NaOH, 0.8-1.2mol / L HCl, deionized water and buffer solution at a flow rate of 150-250μL / h for not less than 25min; through this process, the capillary can be cleaned and infiltrated, so that the electrical properties of the capillary during the electrophoresis field amplification enrichment process are stabilized, which is beneficial to improve the test sensitivity and accuracy of electrophoresis field amplification enrichment; more preferably, before performing capillary electrophoresis field amplification enrichment, the capillary is flushed with 1mol / L NaOH, 1mol / L HCl, deionized water and buffer solution at a flow rate of 200μL / h for 30min.

[0015] Preferably, when continuous determination is performed using capillary electrophoresis field amplification enrichment, the capillary needs to be flushed with a buffer solution for at least 2 minutes between two determinations; flushing can avoid the influence of residual test liquid in two adjacent capillaries on the determination results, thereby improving the determination accuracy.

[0016] Preferably, the buffer solution is 200 mmol / L ammonium formate aqueous solution; auxiliary pressure: 100 mbar; the preferred buffer solution and auxiliary pressure are conducive to the movement and enrichment of amphetamine substances in the buffer solution, the capillary operating current is more stable, and the sensitivity and accuracy of electrophoresis are improved.

[0017] Wherein, preferably, the specific method for determining the content of amphetamine substances in sewage by capillary electrophoresis field amplification enrichment-mass spectrometry comprises the following steps:

[0018] (1) Preparation of reference solution and test solution: preparing amphetamine working solutions with different known concentrations and amphetamine internal standard working solutions with known concentrations respectively; adding amphetamine internal standard working solution to the amphetamine working solution so that the concentrations of the amphetamine internal standard in each solution are the same, thereby obtaining reference solutions with different known concentrations;

[0019] Take the test solution, add the amphetamine internal standard substance working solution, so that the concentration of the amphetamine internal standard substance therein is the same as that of the amphetamine internal standard substance in the reference solution, and prepare the test solution;

[0020] (2) Drawing of a standard curve: taking reference substance solutions of different known concentrations respectively, analyzing them by capillary electrophoresis field amplification enrichment-mass spectrometry, and obtaining a reference substance determination result graph; using the ratio of the peak area of ​​the amphetamine substance in the reference substance solution to the peak area of ​​the amphetamine internal standard substance obtained in the reference substance determination result graph as the ordinate, and the concentration of the amphetamine substance reference substance as the abscissa, drawing a standard curve, and obtaining a linear equation of the standard curve based on the standard curve;

[0021] (3) Determination of the test solution: Take the test solution and analyze it by capillary electrophoresis field amplification enrichment-mass spectrometry to obtain a test solution determination result graph. From the test solution determination result graph, obtain the ratio of the peak area of ​​the amphetamine substance in the test solution to the peak area of ​​the amphetamine internal standard substance. According to the standard curve and linear equation obtained in step (2), calculate the concentration of the amphetamine substance in the test solution.

[0022] Wherein, in step (1), preferably, the concentration of the working solution of amphetamine substances is 0.1 ng / mL, 0.5 ng / mL, 2 ng / mL, 5 ng / mL, 10 ng / mL, and 20 ng / mL, respectively; the preferred working solution concentration is convenient for preparation and calculation of results.

[0023] Preferably, the concentration of the amphetamine internal standard substance working solution is 10 ng / mL; the preferred working solution concentration is convenient for preparation and calculation of results.

[0024] Wherein, in step (2), preferably, the linear equations of the standard curves of amphetamine substances are: The linear equation of methamphetamine is: y=0.0502x+2.7962, R 2 =0.9996; the linear equation of amphetamine is: y = 2.058356x-0.006864, R 2 =0.9998; the linear equation of 3,4-methylenedioxymethamphetamine (MDMA) is: y=16.5248x-0.041167, R 2=0.9983; the linear equation of 3,4-methylenedioxymethylpropylamine (MDA) is: y=3.484204x-0.013449, R 2 =0.9998.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The ultra-sensitive detection method of amphetamines in sewage of the present invention optimizes the type and concentration of buffer solution, the type and concentration of sheath fluid when the content of amphetamines is determined by capillary electrophoresis field amplification enrichment-mass spectrometry in a targeted manner, and increases the auxiliary pressure in a targeted manner, thereby significantly improving the current stability and sensitivity when the amphetamine solution is subjected to capillary electrophoresis field amplification enrichment, thereby better achieving the enrichment and separation of amphetamines in the test solution, significantly improving the detection sensitivity of amphetamines, and achieving a detection limit of 0.1 ng / L. The method is particularly suitable for large-scale application in the detection of trace amphetamines in water samples.

[0027] 2. The ultra-high sensitive detection method of amphetamines in sewage of the present invention has the advantages of simple operation, high sensitivity, low detection cost and short detection time, can accurately determine the content of amphetamines in water, and has good application prospects and use value. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the principle of capillary electrophoresis field amplification enrichment of the present invention (a is the initial state, b is the water plug injection, c is the injection state, and d is the enrichment state);

[0029] Figure 2 The standard curve diagram of the reference substance solution measured by capillary electrophoresis field amplification enrichment-mass spectrometry in Example 1 of the present invention;

[0030] Figure 3 This is a graph showing the capillary electrophoresis field amplification enrichment-mass spectrometry determination results of the test solution in Example 1 of the present invention (FASI-CE-MS / MS spectrum of MAMP with a concentration of 0.1 ng / L (S / N=12.3)). DETAILED DESCRIPTION

[0031] The present invention is further described in detail below in conjunction with test examples and specific implementation methods. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0032] Test equipment: High performance capillary electrophoresis instrument (Agilent 7100, USA) (Principle as Figure 1The instrument was equipped with a triple quadrupole mass spectrometer (Agilent 6470B, USA), and a coaxial sheath flow capillary electrophoresis-mass spectrometer interface (Agilent G1607-60002, USA).

[0033] Capillary column: uncoated fused silica capillary (length 80 cm, inner diameter 50 μm, outer diameter 365 μm).

[0034] Detection objects: methamphetamine, 3,4-methylenedioxymethamphetamine.

[0035] Embodiment 1:

[0036] An ultra-sensitive detection method for methamphetamine in sewage comprises the following steps:

[0037] (1) Preparation of reference solution and test solution: Use ultrapure water to prepare methamphetamine working solutions with concentrations of 0.1 ng / mL, 0.5 ng / mL, 2 ng / mL, 5 ng / mL, 10 ng / mL, and 20 ng / mL, respectively, and deuterated methamphetamine (D5-MAMP) internal standard working solution with a concentration of 10 ng / mL; Accurately measure 980 μL of pure water, add 10 μL of deuterated internal standard working solution of methamphetamine with a concentration of 10 ng / mL to each portion, and then add 10 μL of methamphetamine working solutions with concentrations of 0.1 ng / mL, 0.5 ng / mL, 2 ng / mL, 5 ng / mL, 10 ng / mL, and 20 ng / mL, respectively, to obtain reference solution of methamphetamine with concentrations of 1 ng / L, 5 ng / L, 20 ng / L, 50 ng / L, 100 ng / L, and 200 ng / L, respectively;

[0038] Take 990 μL of the test solution filtered with a 0.22 μm microporous membrane, add a deuterated internal standard working solution of methamphetamine with a concentration of 10 ng / mL, so that the deuterated internal standard concentration of methamphetamine therein is the same as the deuterated internal standard concentration of methamphetamine in the reference solution, and obtain a test solution;

[0039] (2) Drawing of standard curve: respectively taking the reference substance solution in step (1), analyzing it by capillary electrophoresis field amplification enrichment-mass spectrometry, and obtaining a reference substance determination result graph; using the peak area ratio of methamphetamine in the reference substance solution to the peak area ratio of methamphetamine internal standard substance obtained in the reference substance determination result graph as the ordinate, and the methamphetamine reference substance concentration as the abscissa, drawing a standard curve, and according to the standard curve ( Figure 2 ), and the linear equation of the standard curve was obtained (y=0.0502x+2.7962, R 2 =0.9996);

[0040] (3) Test solution determination: Take the test solution and analyze it by capillary electrophoresis field amplification enrichment-mass spectrometry to obtain the test solution determination result diagram ( Figure 3 ), obtain the peak area ratio of methamphetamine in the test solution to the peak area ratio of the methamphetamine internal standard substance in the test solution from the test sample measurement result graph, and calculate the concentration of methamphetamine in the test solution according to the standard curve and linear equation obtained in step (2).

[0041] The capillary electrophoresis field amplification enrichment parameters are as follows: the buffer is 200 mmol / L ammonium formate aqueous solution; the water plug length: 50 mbar pressure water plug inlet 8 s; injection conditions: 30 kV injection 25 s; operating voltage: 20 kV; operating time: 7 min; auxiliary pressure: 100 mbar;

[0042] The sheath liquid of capillary electrophoresis field amplification enrichment-mass spectrometry was 10mmol / L ammonium formate aqueous solution, and the flow rate of the sheath liquid entering the ion source was controlled at 0.5μL / min;

[0043] The mass spectrometry parameters are as follows: detection mode: multiple reaction monitoring (MRM), 2 pairs of parent ion / daughter ion pairs are selected as qualitative ion pairs; ion source parameters: positive ion mode; drying gas temperature is 90°C; drying gas flow rate is 9L / min; nebulizer is 40psi; sheath gas (nitrogen) temperature is 90°C; sheath gas flow rate is 7L / min; capillary voltage is 2100V; nozzle voltage is 600V; other mass spectrometry detection parameters are shown in the following table:

[0044]

[0046] Example 2

[0047] A method for ultra-sensitive detection of methamphetamine in sewage, the specific steps are the same as those of Example 1, except that: the capillary electrophoresis parameters are: the buffer is a 180 mmol / L ammonium formate aqueous solution; the water plug length: 50 mbar pressure water plug inlet 6 s; injection conditions: 30 kV injection 30 s; operating voltage: 22 kV; operating time: 6 min; auxiliary pressure: 150 mbar; the sheath fluid is a 5 mmol / L ammonium formate aqueous solution.

[0048] Example 3

[0049] A method for ultra-sensitive detection of methamphetamine in sewage, the specific steps are the same as those of Example 1, except that: the buffer solution is a 220 mmol / L ammonium formate aqueous solution; the water plug length: 50 mbar pressure water plug inlet 10 s; injection conditions: 30 kV injection 20 s; operating voltage: 18 kV; operating time: 8 min; auxiliary pressure: 50 mbar; the sheath fluid is a 15 mmol / L ammonium formate aqueous solution.

[0050] Example 4

[0051] An ultra-sensitive detection method for 3,4-methylenedioxymethamphetamine in sewage comprises the following steps:

[0052] (1) Preparation of reference solution and test solution: Use ultrapure water to prepare 0.1 ng / mL, 0.5 ng / mL, 2 ng / mL, 5 ng / mL, 10 ng / mL, and 20 ng / mL 3,4-methylenedioxymethamphetamine working solutions and 10 ng / mL 3,4-methylenedioxymethamphetamine deuterated (D5-MDMA) internal standard working solutions; accurately measure 980 μL of pure water and add 10 μL of 10 ng / mL to each solution. Deuterated internal standard working solution of 3,4-methylenedioxymethamphetamine was added, and then 10 μL of 3,4-methylenedioxymethamphetamine working solution with concentrations of 0.1 ng / mL, 0.5 ng / mL, 2 ng / mL, 5 ng / mL, 10 ng / mL, and 20 ng / mL were added respectively to obtain reference substance solutions of 3,4-methylenedioxymethamphetamine with concentrations of 1 ng / L, 5 ng / L, 20 ng / L, 50 ng / L, 100 ng / L, and 200 ng / L respectively;

[0053] Take 990 μL of the test solution filtered with a 0.22 μm microporous filter membrane, add a deuterated internal standard working solution of 3,4-methylenedioxymethamphetamine with a concentration of 10 ng / mL, so that the deuterated internal standard concentration of 3,4-methylenedioxymethamphetamine therein is the same as the deuterated internal standard concentration of 3,4-methylenedioxymethamphetamine in the reference solution, and obtain a test solution;

[0054] (2) Drawing of a standard curve: Take the reference solution in step (1) respectively, analyze it by capillary electrophoresis field amplification enrichment-mass spectrometry, and obtain a reference measurement result graph; use the peak area ratio of 3,4-methylenedioxymethamphetamine in the reference solution to the peak area ratio of 3,4-methylenedioxymethamphetamine deuterated internal standard substance obtained in the reference measurement result graph as the ordinate, and the concentration of 3,4-methylenedioxymethamphetamine reference substance as the abscissa to draw a standard curve, and obtain the linear equation of the standard curve (y=3.484204x-0.013449, R 2=0.9998);

[0055] (3) Determination of test solution: Take the test solution and analyze it by capillary electrophoresis field amplification enrichment-mass spectrometry to obtain a test solution determination result graph. From the test solution determination result graph, obtain the ratio of the peak area of ​​3,4-methylenedioxymethamphetamine in the test solution to the peak area of ​​the deuterated internal standard substance of 3,4-methylenedioxymethamphetamine. Calculate the concentration of 3,4-methylenedioxymethamphetamine in the test solution based on the standard curve and linear equation obtained in step (2).

[0056] The capillary electrophoresis field amplification enrichment parameters are as follows: the buffer is 200 mmol / L ammonium formate aqueous solution; the water plug length: 50 mbar pressure water plug inlet 8 s; injection conditions: 30 kV injection 25 s; operating voltage: 20 kV; operating time: 7 min; auxiliary pressure: 100 mbar;

[0057] The sheath liquid of capillary electrophoresis field amplification enrichment-mass spectrometry was 10mmol / L ammonium formate aqueous solution, and the flow rate of the sheath liquid entering the ion source was controlled at 0.5μL / min;

[0058] The mass spectrometry parameters are as follows: detection mode: multiple reaction monitoring (MRM), 2 pairs of parent ion / daughter ion pairs are selected as qualitative ion pairs; ion source parameters: positive ion mode; drying gas temperature is 90°C; drying gas flow rate is 9L / min; nebulizer is 40psi; sheath gas (nitrogen) temperature is 90°C; sheath gas flow rate is 7L / min; capillary voltage is 2100V; nozzle voltage is 600V; other mass spectrometry detection parameters are shown in the following table:

[0059] Comparative Example 1

[0060] A method for detecting methamphetamine content, wherein the specific steps are the same as those of Example 1, except that the buffer solution is a 200 mmol / L ammonium formate aqueous solution, and formic acid is added to adjust the pH to 3.0.

[0061] Comparative Example 2

[0062] A method for detecting methamphetamine content, wherein the specific steps are the same as those of Example 1, except that the buffer solution is a 150 mmol / L ammonium formate aqueous solution.

[0063] Comparative Example 3

[0064] A method for detecting methamphetamine content, wherein the specific steps are the same as those of Example 1, except that the buffer solution is a 250 mmol / L ammonium formate aqueous solution.

[0065] Comparative Example 4

[0066] A method for detecting methamphetamine content, wherein the specific steps are the same as those of Example 1, except that no auxiliary pressure is used during capillary electrophoresis field amplification enrichment.

[0067] Comparative Example 5

[0068] A method for detecting methamphetamine content, wherein the specific steps are the same as those of Example 1, except that the auxiliary pressure during capillary electrophoresis field amplification enrichment is 50 mbar.

[0069] Comparative Example 6

[0070] A method for detecting methamphetamine content, wherein the specific steps are the same as those of Example 1, except that the auxiliary pressure during capillary electrophoresis field amplification enrichment is 150 mbar.

[0071] Comparative Example 7

[0072] A method for detecting methamphetamine content, wherein the specific steps are the same as those of Example 1, except that the sheath fluid is a 5 mmol / L formic acid aqueous solution.

[0073] Comparative Example 8

[0074] A method for detecting methamphetamine content, wherein the specific steps are the same as those of Example 1, except that the sheath fluid is a 5 mmol / L ammonium formate aqueous solution.

[0075] Comparative Example 9

[0076] A method for detecting methamphetamine content, wherein the specific steps are the same as those of Example 1, except that the sheath fluid is a 15 mmol / L ammonium formate aqueous solution.

[0077] Comparative Example 10

[0078] A method for detecting methamphetamine content, wherein the specific steps are the same as those in Example 1, except that a fused silica capillary (length 80 cm, inner diameter 50 μm, outer diameter 365 μm) with a PVA coating is selected as the capillary.

[0079] Experimental Example: The same methamphetamine standard solution (methamphetamine concentration of 100 ng / L) was tested for content using the detection methods of Examples 1-3 and Comparative Examples 1-10 (5 parallel tests, average value taken); the standard solution of 3,4-methylenedioxymethamphetamine (concentration of 100 ng / L) was tested using the detection method of Example 4, and the test results are as follows:

[0080]

[0081]

[0082] It is known that the detection of methamphetamine-like substances is carried out by the inventive method in embodiment 1-4, with high sensitivity, the advantage of high accuracy, and the error percentage of detection result and actual concentration is within 5%; and any parameter (comparative example 1-10) in the change detection method, can have a strong impact on the sensitivity and accuracy of the detection method, cause the error percentage of the detection result to increase significantly, and even cannot obtain the detection result (comparative example 1 and 4). In comparative example 5, the auxiliary pressure during the capillary electrophoresis field amplification enrichment is too small, and the peak time in the mass spectrum is also caused to be behind, and the auxiliary pressure in comparative example 6 is too large, and the peak time in the mass spectrum is caused to be ahead, which significantly affects the sensitivity of detection and the accuracy of the result.

Claims

1. An ultra-sensitive detection method for amphetamines in sewage, characterized in that: include: The content of amphetamines in sewage was determined by capillary electrophoresis field amplification enrichment-mass spectrometry. Wherein, the amphetamine-type substance includes at least one of MAMP, AMP, MDMA, and MDA; The capillary electrophoresis field amplification enrichment parameters are: the buffer is 180-220 mmol / L ammonium formate aqueous solution; the water plug length: 50 mbar pressure water plug injection 6-10 s; injection conditions: 30 kV injection 20-30 s; operating voltage: 18-22 kV; operating time: 6-8 min; auxiliary pressure: 80-120 mbar; The capillary electrophoresis field amplification enrichment-mass spectrometry method uses a coaxial sheath flow interface to connect the capillary electrophoresis instrument and the mass spectrometer; the sheath flow liquid is 8-12 mmol / L ammonium formate aqueous solution, and the flow rate of the sheath flow liquid entering the ion source is controlled at 0.5 μL / min; The mass spectrometry parameters are: detection mode: multiple reaction monitoring, two pairs of parent ion / daughter ion pairs are selected as qualitative ion pairs; ion source parameters: positive ion mode; drying gas temperature is 90 °C; drying gas flow rate is 9 L / min; nebulizer is 40 psi; sheath gas temperature is 90 °C; sheath gas flow rate is 7 L / min; capillary voltage is 2100 V; nozzle voltage is 600 V; other mass spectrometry detection parameters of different amphetamine substances are shown in the following table:

2. The ultra-sensitive detection method of amphetamines in sewage according to claim 1, characterized in that: The capillaries used in capillary electrophoresis field amplification enrichment were uncoated fused silica capillaries.

3. The ultra-sensitive detection method of amphetamines in sewage according to claim 2, characterized in that: The capillary has a length of 80-100 cm, an inner diameter of 50 μm, and an outer diameter of 365 μm.

4. The ultra-sensitive detection method of amphetamines in sewage according to claim 1, characterized in that: Before capillary electrophoresis field amplification enrichment, the capillary was flushed with 0.8-1.2 mol / L NaOH, 0.8-1.2 mol / L HCl, deionized water and buffer solution at a flow rate of 150-250 μL / h for no less than 25 min.

5. The ultra-sensitive detection method for amphetamines in sewage according to claim 4, characterized in that: Before capillary electrophoresis field amplification enrichment, the capillary was flushed with 1 mol / L NaOH, 1 mol / L HCl, deionized water and buffer solution at a flow rate of 200 μL / h for 30 min.

6. The ultra-sensitive detection method of amphetamines in sewage according to claim 1, characterized in that: When continuous determination is performed using capillary electrophoresis field amplification enrichment, the capillary needs to be flushed with the buffer for at least 2 minutes between two determinations.

7. The ultra-sensitive detection method of amphetamines in sewage according to claim 1, characterized in that: The buffer solution is 200 mmol / L ammonium formate aqueous solution; the auxiliary pressure is 100 mbar.

8. The ultra-sensitive detection method for amphetamines in sewage according to any one of claims 1 to 7, characterized in that: The specific method for determining the content of amphetamines in sewage by capillary electrophoresis field amplification enrichment-mass spectrometry comprises the following steps: (1) Preparation of reference solution and test solution: prepare working solutions of amphetamine substances with different known concentrations and working solutions of amphetamine internal standard substances with known concentrations, respectively; add the working solution of amphetamine internal standard substances to the working solutions of amphetamine substances so that the concentrations of amphetamine internal standard substances in each solution are the same, thereby obtaining reference solution with different known concentrations; Take the test solution, add the amphetamine internal standard substance working solution, so that the concentration of the amphetamine internal standard substance therein is the same as that of the amphetamine internal standard substance in the reference solution, and prepare the test solution; (2) Drawing of standard curve: Take reference substance solutions of different known concentrations and analyze them by capillary electrophoresis field amplification enrichment-mass spectrometry to obtain a reference substance determination result graph; use the ratio of the peak area of ​​amphetamine substances in the reference substance solution to the peak area of ​​amphetamine internal standard substances obtained in the reference substance determination result graph as the ordinate and the concentration of amphetamine reference substance as the abscissa to draw a standard curve, and obtain the linear equation of the standard curve based on the standard curve; (3) Determination of test solution: Take the test solution and analyze it by capillary electrophoresis field amplification enrichment-mass spectrometry to obtain a test solution determination result graph. From the test solution determination result graph, obtain the ratio of the peak area of ​​the amphetamine-like substance in the test solution to the peak area of ​​the amphetamine-like internal standard substance. According to the standard curve and linear equation obtained in step (2), calculate the concentration of the amphetamine-like substance in the test solution.

9. The ultra-sensitive detection method for amphetamines in sewage according to claim 8, characterized in that: In step (1), the concentrations of the working solutions of amphetamine-type substances are 0.1 ng / mL, 0.5 ng / mL, 2 ng / mL, 5 ng / mL, 10 ng / mL, and 20 ng / mL, respectively; the concentration of the working solution of the amphetamine-type internal standard substance is 10 ng / mL.

10. The ultra-sensitive detection method for amphetamines in sewage according to claim 8, characterized in that: In step (2), the linear equations of the standard curves of amphetamine substances are: The linear equation of methamphetamine is: y = 0.0502x + 2.7962, R 2 = 0.9996; the linear equation for amphetamine is: y = 2.058356x -0.006864, R 2 = 0.9998; the linear equation of 3,4-methylenedioxymethamphetamine is: y = 16.5248x -0.041167, R 2 = 0.9983; the linear equation of 3,4-methylenedioxymethylpropylamine is: y =3.484204x -0.013449, R 2 = 0.9998.

Images