Carbamate compound separation ionization integrated mass spectrometry ionization device and application

Abstract

The application discloses a separation and ionization integrated mass spectrum ionization device for detecting carbamate compounds and application, wherein the separation and ionization integrated mass spectrum ionization device comprises a sample carrier table, the sample carrier table comprises a support frame, an extraction element, one end of the extraction element is connected with the support frame, the extraction element comprises a conductive layer formed by stainless steel, an extraction layer located on at least part of the surface of the conductive layer, the extraction layer is formed by a molecularly imprinted graphene oxide composite material, wherein the molecular imprinting of the molecularly imprinted graphene oxide composite material is obtained by polymerization of isoprocarb as a template molecule and methacrylic acid (MAA) as a functional monomer, and a high-voltage power supply connected with the extraction element. The device can realize high-specificity enrichment separation and ionization ionization and mass spectrum detection of carbamate compounds, and is suitable for on-site, rapid and high-selectivity mass spectrum detection of carbamate compounds.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of analytical chemistry, in particular, to a separation and ionization integrated mass spectrometry ionization device for carbamate compound detection. BACKGROUND

[0002] Carbamate pesticides (CPs) are a class of synthetic pesticides. Compared with organophosphorus pesticides, CPs have the advantages of small dosage, high efficacy, short residence time, and fast decomposition rate, and are widely used in agriculture, forestry, and animal husbandry. However, due to the unreasonable use in agricultural production, the CPs residues in the environment and food will affect the health of humans and animals. It is essential to detect CPs residues in the environment and food. At present, the main detection device for CPs is chromatography and chromatography-mass spectrometry combined system. The detection limit of chromatography is relatively high, and the detection of chromatography-mass spectrometry combined system is time-consuming. Moreover, both of the two detection devices need complex pretreatment processes such as extraction, purification, and enrichment.

[0003] Therefore, the device for quantitative detection of carbamate pesticides needs to be improved. SUMMARY

[0004] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, one object of the present application is to provide a separation and ionization integrated mass spectrometry ionization device, which does not need to use chromatographic separation, has a simple detection process, and fast detection speed.

[0005] It should be noted that the present application is based on the following work of the inventor:

[0006] Open ionization technology is the core of open mass spectrometry. Without or with only minor pretreatment, samples are directly ionized in the atmosphere to quickly obtain molecular information of the samples. At present, various forms of open ionization technology have been developed, such as direct analysis in real time (DART), extractive electrospray ionization (EESI), dielectric barrier discharge ionization (DBDI), low-temperature plasma (LTP), etc. Since the paper-based open electrospray ionization technology was first reported in 2010, other types of solid materials have also been tried as substrates to load samples for direct electrospray ionization, such as wood, metal, biological tissue, etc. This open mass spectrometry using solid substrates to carry samples to generate electrospray ionization is called solid substrate electrospray ionization mass spectrometry (SSEI-MS). SSEI-MS has been reported to be applied to the analysis of small molecule compounds to biological macromolecules. When facing the target substances at trace or even trace level in complex matrix, the detection sensitivity problem of solid substrate electrospray ionization mass spectrometry begins to stand out. Because the solid substrate has no selectivity or poor selectivity for the target substance, the matrix effect is obvious, the instrument detection limit is high, and it is difficult to realize accurate determination of trace substances. In view of this problem, the inventors reformed the existing chromatography-mass spectrometry system, and cooperated with a mass spectrometry ionization device with high specificity to extract and separate the carbamate compounds with high specificity, and then sprayed the extract into the mass spectrometer for detection under high pressure, solving the problem that the solid substrate electrospray ionization mass spectrometry has no selectivity or poor selectivity for the target substance, the detection steps are simple, and the background noise of the detection is low and the specificity is high.

[0007] Therefore, according to one aspect of the present application, the present application provides a separation and ionization integrated mass spectrometry ionization device for carbamate compound detection. According to an embodiment of the present application, the device comprises: a sample stage, the sample stage comprising: a support frame; an extraction element, one end of the extraction element being connected with the support frame, the extraction element comprising: a conductive layer, the conductive layer being formed of stainless steel; an extraction layer, the extraction layer being located on at least part of the surface of the conductive layer, the extraction layer being formed of a molecularly imprinted graphene oxide composite material, wherein the molecular imprint of the molecularly imprinted graphene oxide composite material is obtained by polymerization of isoprocarb as a template molecule and methacrylic acid (MAA) as a functional monomer; and a high-voltage power supply, the high-voltage power supply being connected with the extraction element.

[0008] The separation and ionization integrated mass spectrometry ionization device for carbamate compound detection according to the embodiment of the present application adopts an extraction element of a molecularly imprinted graphene oxide composite material modified stainless steel plate, which has good specific adsorption and enrichment effect on carbamate compounds, especially carbamate pesticides, has strong specificity in extraction and enrichment, and has simple detection steps.

[0009] In addition, the separation and ionization integrated mass spectrometry ionization device for detecting carbamate compounds according to the above-mentioned embodiments of the present application can further have the following additional technical features:

[0010] According to the embodiments of the present application, the extraction element is an isosceles triangle, the length of the legs of the isosceles triangle is 1.5-2.5 cm, and the base is 0.5-1.5 cm.

[0011] According to the embodiments of the present application, the thickness of the conductive layer is 0.1-0.5 mm.

[0012] According to the embodiments of the present application, the thickness of the extraction layer is 50-200 μm.

[0013] According to the embodiments of the present application, the method for preparing the extraction element includes: acidizing a stainless steel sheet to obtain an acidized steel sheet; adhering graphene powder to the acidized steel sheet to obtain a graphene-attached steel sheet; contacting the template molecule, the functional monomer, and a porogen to perform a prepolymerization reaction to obtain a prepolymerization solution; and dissolving a crosslinking agent and an initiator in the prepolymerization solution, and then immersing at least a portion of the graphene-attached steel sheet in the prepolymerization solution to perform a polymerization reaction to obtain the extraction element.

[0014] According to the embodiments of the present application, the graphene powder is adhered to the acidized steel sheet using a silicone adhesive solution.

[0015] According to the embodiments of the present application, the crosslinking agent is ethylene glycol dimethacrylate (EGDMA).

[0016] According to the embodiments of the present application, the molar ratio of the template molecule to the monomer and the crosslinking agent is 1:5-7:30-35.

[0017] According to the embodiments of the present application, the initiator is azobisisobutyronitrile (AIBN).

[0018] According to the embodiments of the present application, the porogen is a mixed solution of chloroform and methanol, and preferably, the volume ratio of the chloroform and the methanol is 4-6:1.

[0019] According to an embodiment of the present application, the method for preparing the extraction element comprises: immersing the stainless steel sheet into a 1-2 mol / L sulfuric acid solution, rinsing the surface of the steel sheet to neutral after ultrasonic treatment for 0.5-1.0 hours, and drying with nitrogen to obtain the acidified steel sheet; coating the acidified steel sheet with the silicone glue solution, adhering the graphene oxide powder on the steel sheet, drying at 40-60℃ for 30 minutes, and cleaning with methanol ultrasonic to obtain the steel sheet with graphene oxide coating; adding the template molecule and the functional monomer into the porogen, pre-polymerizing at room temperature for 2-4 hours to obtain a pre-polymerization solution; dissolving the cross-linking agent and the initiator into the pre-polymerization solution, immersing at least part of the graphene-attached steel sheet into the pre-polymerization solution, and polymerizing at 55-70℃ for 12-24 hours in an oxygen-free environment to obtain an extraction element preliminary product; and performing elution treatment on the extraction element preliminary product with an elution solution to obtain the extraction element.

[0020] According to another aspect of the present application, the present application provides a mass spectrometer. According to an embodiment of the present application, the mass spectrometer comprises: a mass spectrometer detector comprising a sample inlet; and the aforementioned separation and ionization integrated mass spectrometer ionization device for carbamate pesticide detection, wherein the extraction element of the integrated mass spectrometer ionization device is arranged opposite to the sample inlet.

[0021] According to the mass spectrometer of the present application, the integrated mass spectrometer ionization device is used to extract the carbamate compound with high specificity, and then the extract is ionized into the mass spectrometer detector for detection, thereby solving the problem that the existing mass spectrometer has no selectivity or poor selectivity for the target substance, and the adsorption and enrichment effect of the carbamate compound is good, the detection steps are simple, the specificity is good, and the accuracy and sensitivity are high.

[0022] According to an embodiment of the present application, the top corner of the extraction element is arranged opposite to the sample inlet.

[0023] According to another aspect of the present application, the present application provides the aforementioned integrated mass spectrometer ionization device and the aforementioned mass spectrometer for detecting the content of carbamate compounds. Thus, the detection steps are simple, the background noise of the detection is low, and the specificity is high. In addition, it should be noted that the mass spectrometer ionization device has all the technical features and technical effects of the aforementioned mass spectrometer ionization device, and the mass spectrometer also has all the technical features and technical effects of the aforementioned mass spectrometer, which will not be described here.

[0024] According to an embodiment of the present application, the carbamate compound is at least one of carbaryl (CAR), butocarboxim (BPMC), carbofuran (CBF), isoprocarb (MICP), and propoxur (PPX).

[0025] According to another aspect of the present application, the present application provides a method for detecting the content of carbamate compounds in a sample to be tested. According to an embodiment of the present application, the method comprises: contacting the sample to be tested with the extraction element of the integrated mass spectrometry ionization device, so as to extract the carbamate compounds in the sample to be tested; dropping the spray desorption solvent on the surface of the extraction element to desorb the extracted carbamate compounds; and ionizing the desorbed carbamate compounds by the high-voltage power supply and entering the mass spectrometry detector for detection, so as to obtain the content of the carbamate compounds in the sample to be tested.

[0026] According to an embodiment of the present application, the extraction is performed under the condition of shaking at 450 rpm for 5-30 minutes, preferably for 20 minutes.

[0027] According to an embodiment of the present application, the volume of the sample to be tested is 2-15 mL, preferably 10 mL.

[0028] According to an embodiment of the present application, the distance between the tip of the extraction element and the inlet of the mass spectrometry detector is 3-8 mm, preferably 5 mm.

[0029] According to an embodiment of the present application, the mass spectrometry ionization condition of the integrated mass spectrometry ionization device is that the spray voltage of the high-voltage power supply is 2.5-5 kV, preferably 3.5 kV.

[0030] According to an embodiment of the present application, the spray desorption solvent is a methanol solution containing (0-1)% formic acid, and the volume of the desorption solvent is 10-30 μL, preferably 20 μL.

[0031] According to an embodiment of the present application, the detection condition of the mass spectrometry detector is that the detection mode is multiple reaction monitoring (MRM), the atomization gas pressure is 55 psi, the auxiliary gas pressure is 50 psi, the curtain gas pressure is 20 psi, the ion source temperature is 550°C, and the residence time is 100 ms.

[0032] Additional aspects and advantages of the present application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0033] The above and / or additional aspects and advantages of the present application will become apparent and be readily appreciated from the following description, including the appended drawings.

[0034] Figure 1 A structural schematic diagram of an integrated mass spectrometry ionization device according to an embodiment of the present application is shown.

[0035] Figure 2 shows a structural schematic diagram of an extraction element according to an embodiment of the present application;

[0036] Figure 3 shows a structural schematic diagram of a mass spectrometer according to an embodiment of the present application;

[0037] Figure 4 shows a flow schematic diagram of a method for detecting the content of carbamate compounds in a sample to be tested according to an embodiment of the present application;

[0038] Figure 5 shows a result schematic diagram of the influence of different extraction times on 5 kinds of carbamate pesticides according to an embodiment of the present application;

[0039] Figure 6 shows a result schematic diagram of the influence of different extraction solvent volumes on 5 kinds of carbamate pesticides according to an embodiment of the present application;

[0040] Figure 7 shows a result schematic diagram of the influence of different pH values of extraction solvents on 5 kinds of carbamate pesticides according to an embodiment of the present application;

[0041] Figure 8 shows a result schematic diagram of the influence of different ionic strengths of extraction solvents on 5 kinds of carbamate pesticides according to an embodiment of the present application;

[0042] Figure 9 shows a result schematic diagram of the influence of different spray voltages on 5 kinds of carbamate pesticides according to an embodiment of the present application;

[0043] Figure 10 shows a result schematic diagram of the influence of different spray ionization solvents on 5 kinds of carbamate pesticides according to an embodiment of the present application. DETAILED DESCRIPTION

[0044] Embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout the drawings denote the same or similar elements or elements having the same or similar functions. The embodiments described below by reference to the drawings are exemplary only, and are used only for explanation of the present application, and cannot be understood as a limitation of the present application.

[0045] It should be noted that the terms "first", "second" are used only for descriptive purpose, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more of the features. Further, in the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specified.

[0046] According to an aspect of the present application, the present application provides a separation and ionization integrated mass spectrometry ionization device for carbamate compound detection. The extraction element of the integrated mass spectrometry ionization device according to the embodiments of the present application is a molecularly imprinted graphene oxide composite modified stainless steel plate, which has good specific adsorption and enrichment effect on carbamate compounds, strong specific extraction and enrichment, simple detection steps, and high accuracy and sensitivity of detection. In some embodiments, the enrichment factor of the integrated mass spectrometry ionization device according to the embodiments of the present application for five kinds of carbamate compounds is 70.75-467.38, the device has good linear detection range, and the recovery rate in the sample is 80.21-91.11%.

[0047] Reference Figure 1 According to the embodiments of the present application, the device 100 comprises a sample stage 160 and a high-voltage power supply 130, wherein the sample stage 160 comprises a support frame 110 and an extraction element 120, and one end of the extraction element 120 is connected to the support frame 110. Reference Figure 2 According to the embodiments of the present application, the extraction element comprises a conductive layer 121 and an extraction layer 122, wherein the conductive layer 121 is formed of stainless steel; the extraction layer is located on at least part of the surface of the conductive layer, and the extraction layer is formed of a molecularly imprinted graphene oxide composite; the molecular imprint of the molecularly imprinted graphene oxide composite is obtained by polymerization of isoprocarb as a template molecule and methacrylic acid (MAA) as a functional monomer; and the high-voltage power supply is connected to the extraction element.

[0048] According to the embodiments of the present application, the extraction element is an isosceles triangle, the length of the legs of the isosceles triangle is 1.5-2.5 cm, and the base is 0.5-1.5 cm. Therefore, the stainless steel sheet of the extraction element is an isosceles triangle, and the angle of the extraction element with the above dimensions is appropriate, forming a spray Taylor cone at the tip of the triangle. If the angle is too small or too large, the elution solvent will be hindered by surface tension to form a spray.

[0049] The inventors have found that the thickness of the conductive layer affects the effect of the elution solvent forming an electrospray at the tip of the conductive layer, and the thinner the conductive layer, the better the effect of forming an electrospray. According to an embodiment of the present application, the thickness of the conductive layer is 0.1-0.5 mm. In this way, the thickness of the conductive layer is small, and the effect of forming an electrospray is good.

[0050] According to an embodiment of the present application, the thickness of the extraction layer is 50-200 μm. The thicker the thickness of the extraction layer, the more the number of layers between the repeat units of the covalent organic framework material, and the greater the adsorption capacity. However, if the thickness of the extraction layer is too thick, it will increase the extraction time and the difficulty of elution, and reduce the extraction efficiency and the reusability of the extraction element. The extraction layer of the embodiment of the present application has a suitable thickness in the above range, a large number of layers, and a large adsorption capacity.

[0051] According to an embodiment of the present application, the method for preparing the extraction element comprises: subjecting a stainless steel sheet to acid treatment to obtain an acid-treated steel sheet; adhering graphene powder to the acid-treated steel sheet to obtain a graphene-attached steel sheet; contacting the template molecule, the functional monomer, and the porogen to perform a prepolymerization reaction to obtain a prepolymerization solution; and dissolving a crosslinking agent and an initiator in the prepolymerization solution, and then immersing at least a portion of the graphene-attached steel sheet in the prepolymerization solution to perform a polymerization reaction, thereby obtaining the extraction element. In this way, the prepared extraction element has good specific adsorption and enrichment of the compound to be extracted and its structural analogs, the specificity of extraction and enrichment is high, the detection steps are simplified, and the background noise of detection is low and the specificity is high.

[0052] According to an embodiment of the present application, the graphene powder is adhered to the acid-treated steel sheet by using a silicone glue solution. According to an embodiment of the present application, the crosslinking agent is ethylene glycol dimethacrylate (EGDMA). According to an embodiment of the present application, the molar ratio of the template molecule to the monomer and the crosslinking agent is 1:5-7:30-35. In this way, the template molecule and the functional monomer form a composite material layer on the surface of the steel sheet under the action of the crosslinking agent, and the composite material layer has good selectivity and multiple adsorption sites for carbamate compounds, and can adsorb the carbamate compounds on the voids of the molecularly imprinted polymer through multiple interaction forces, and has good selectivity and strong adsorption. In addition, the proportion of the functional monomer grafted to the crosslinking agent is suitable, and under this proportion, the crosslinking agent and the initiator can effectively initiate the polymerization reaction, and the formed molecularly imprinted polymer has a good imprinting effect.

[0053] According to an embodiment of the present application, the initiator is azobisisobutyronitrile (AIBN). In this way, the efficiency of catalyzing the crosslinking reaction is high.

[0054] According to the embodiment of the present application, the porogen is a mixed solution of chloroform and methanol. In this way, the porogen can effectively dissolve the template molecules, and make the template molecules stably combine with the functional monomers, and fully play the role of the porogen, and promote the cross-linked material to form a three-dimensional hole that matches the size and shape of the template molecules and accommodates the to-be-tested compounds. According to the preferred embodiment of the present application, the volume ratio of chloroform to methanol is 4-6:1. In this way, the stability of the combination of the template molecules and the functional monomers is high, and the pore size of the formed adsorption material is suitable.

[0055] According to the embodiment of the present application, the modified stainless steel sheet is immersed in the cross-linked polymer, filled with nitrogen, and pre-polymerized at room temperature for 4-6 hours. According to the specific embodiment of the present application, after pre-polymerization at room temperature for 4-6 hours, the vacuum pump is sealed under negative pressure in a nitrogen environment, and polymerization is carried out at 55-65 ℃ for 12-18 hours, preferably for 12 hours.

[0056] According to the embodiment of the present application, the elution treatment is carried out by using an eluent, and specifically, the eluent is a mixed solution of methanol and formic acid, and preferably, the eluent is a methanol solution containing 8-12% acetic acid.

[0057] According to the embodiment of the present application, the elution treatment can be carried out by immersing the coated stainless steel sheet in the eluent for 30 minutes, and repeatedly eluting 6-18 times, preferably 12 times. After elution, the stainless steel sheet is washed with ultrapure water until it is neutral, and then acetone is used for washing and drying. In this way, the template molecules on the cross-linked polymer can be fully removed.

[0058] According to the embodiment of the present application, the method for preparing the extraction element includes the following steps: immersing the stainless steel sheet in a 1-2 mol / L sulfuric acid solution, ultrasonic treatment for 0.5-1.0 hours, then washing the surface of the steel sheet with water until it is neutral, and then blowing dry with nitrogen, so as to obtain the acidified steel sheet; coating the acidified steel sheet with the silicone glue solution, adhering the graphene oxide powder on the steel sheet, drying at 40-60 ℃ for 30 minutes, and then ultrasonic cleaning with methanol, so as to obtain the steel sheet with a graphene oxide coating; adding the template molecules and the functional monomers into the porogen, pre-polymerizing at room temperature for 2-4 hours to carry out a pre-polymerization reaction, so as to obtain a pre-polymerization solution; dissolving the cross-linking agent and the initiator in the pre-polymerization solution, immersing at least part of the graphene-attached steel sheet in the pre-polymerization solution, carrying out polymerization at 55-70 ℃ for 12-24 hours in an oxygen-free environment to carry out a polymerization reaction, so as to obtain an extraction element preliminary product; and carrying out elution treatment on the extraction element preliminary product by using an elution solution, so as to obtain the extraction element.

[0059] According to the embodiment of the present application, the high-voltage power supply 130 is connected to the extraction element fixer 140 through a wire. The wire transmits power to the extraction element, has excellent electrical conductivity, and preferably, the wire is selected to be a copper wire.

[0060] According to an embodiment of the present application, the sample stage 160 further comprises an X translation rail and a Y translation rail, and the support frame 110 is arranged on the X translation rail and the Y translation rail so as to be movable, and the platform fixer is arranged at the lower end of the vertical support rod 110 so as to fix the mass spectrometry ion source device 100 at a specific position.

[0061] According to an embodiment of the present application, the components of the mass spectrometry ionization device 100 are detachable, which facilitates the movement.

[0062] According to another aspect of the present application, the present application provides a mass spectrometer. Figure 3 According to an embodiment of the present application, the mass spectrometer comprises a mass spectrometry detector 200 and the aforementioned integrated mass spectrometry ionization device 100, wherein the mass spectrometry detector 200 comprises a sample inlet 210, and the extraction element 120 of the integrated mass spectrometry ionization device 100 is arranged opposite to the sample inlet 210.

[0063] The mass spectrometer according to an embodiment of the present application extracts carbamate compounds with high specificity through the integrated mass spectrometry ionization device, and then ionizes the extract to enter the mass spectrometry detector for detection, thereby solving the problem that the existing mass spectrometry has no selectivity or poor selectivity for target substances, and the detection step is simple and the specificity is high. In some embodiments, the enrichment factor of the integrated mass spectrometry ionization device according to an embodiment of the present application for five kinds of carbamate compounds is 70.75-467.38, the device has a good linear detection range, and the recovery rate in the sample is 80.21-91.11%.

[0064] According to an embodiment of the present application, the top corner of the extraction element 120 is arranged opposite to the mass spectrometry sample inlet 210.

[0065] According to an embodiment of the present application, the distance between the extraction element 120 and the mass spectrometry sample inlet 210 is 3-8 mm. The inventors have found that when the voltage applied to the extraction element 120 is fixed, the distance between the tip of the extraction element 120 and the mass spectrometry sample inlet 210 has an important influence on the response of the mass spectrometry. If the distance between the extraction element and the sample inlet is too close, the voltage will be broken down, damaging the instrument; if the distance between the extraction element and the sample inlet is too far, the detection signal will be weak. According to an embodiment of the present application, the distance between the extraction element 120 and the mass spectrometry sample inlet 210 is 5 mm. Thus, the mass spectrometry response value is high, and the instrument can be protected from damage.

[0066] According to another aspect of the present application, the present application provides a use of the aforementioned mass spectrometry ionization device and the aforementioned mass spectrometer in detecting the content of carbamate compounds. Thus, the detection step is simple, the background noise of the detection is low, the throughput is high, and the specificity is high. In addition, it should be noted that the mass spectrometry ionization device has all the technical features and technical effects of the aforementioned mass spectrometry ionization device, and the mass spectrometer also has all the technical features and technical effects of the aforementioned mass spectrometer, which will not be repeated here.

[0067] According to an embodiment of the present application, the carbamate compound is at least one of carbaryl (CAR), bucfonate (BPMC), carbofuran (CBF), isoprocarb (MICP), and propoxur (PPX).

[0068] According to another aspect of the present application, the present application provides a method for detecting the content of carbamate compounds in a to-be-tested sample. Referring to Figure 4 , according to an embodiment of the present application, the method comprises:

[0069] S100 extraction treatment

[0070] The to-be-tested sample is contacted with the extraction element of the aforementioned mass spectrometer, so as to extract the carbamate compounds in the to-be-tested sample.

[0071] According to an embodiment of the present application, the to-be-tested sample can be an environmental water sample, fruit juice, tea beverage, milk, etc.

[0072] According to an embodiment of the present application, the to-be-tested sample is further subjected to impurity removal treatment before the extraction treatment. It should be noted that the methods for removing impurities and extraction are different for different samples, and those skilled in the art can choose according to their own experience. Generally, the to-be-tested sample can be directly detected after centrifugal filtration. According to some embodiments of the present application, the volume of the to-be-tested sample is 2-15 mL, preferably 10 mL.

[0073] The inventors have found that when the volume of the to-be-tested solution is in the range of 2-10 mL, the adsorption amount increases with the increase of the sample amount. When the sample volume continues to increase (10-15 mL), the adsorption amount does not change significantly. According to an embodiment of the present application, the volume of the to-be-tested solution is 8-12 mL, the adsorption amount of the extraction element is large, and preferably, the volume of the to-be-tested solution is 10 mL, the adsorption amount of the extraction element is better.

[0074] According to the embodiment of the present application, the extraction process is performed under the condition of 450 rpm shaking for 5-30 minutes, preferably 20 minutes. The inventors have found that the binding rate of the target compound to the extraction element generally increases significantly within 5-20 minutes and approaches equilibrium within 20-30 minutes after the extraction element is contacted with the sample to be tested. Further, according to the embodiment of the present application, at least part of the extraction element is immersed in the solution to be tested, and is contacted for 5-30 minutes, preferably 20 minutes, under the condition of 450 rpm shaking. Thus, the compound is allowed to bind to the extraction element sufficiently, so that the accuracy and recovery rate of the detection are higher.

[0075] S200 desorption

[0076] The carbamate compound extracted from the extraction element is desorbed by adding a spray desorption solvent on the surface of the extraction element.

[0077] According to the embodiment of the present application, the elution process can be performed by immersing the coated stainless steel sheet in the eluent for 30 minutes, and repeating the elution for 6-18 times, preferably 12 times. After elution, the stainless steel sheet is washed with ultrapure water until neutral, and is washed with acetone and dried for standby. Thus, the template molecules on the cross-linked polymer are removed sufficiently.

[0078] S300 mass spectrometry detection

[0079] The desorbed carbamate compound is ionized by a high-voltage power supply, and is detected by a mass spectrometry detector, so as to obtain the content of the carbamate compound in the sample to be tested.

[0080] According to the embodiment of the present application, the distance between the tip of the extraction element and the inlet of the mass spectrometry detector is 3-8 mm, preferably 5 mm. Thus, the ionized spray is allowed to enter the detector sufficiently.

[0081] According to the embodiment of the present application, the ionization condition of the integrated mass spectrometry ionization is that the spray voltage of the high-voltage power supply is 2.5-5 kV, preferably 3.5 kV. Thus, when the voltage of the high-voltage power supply is 0-3.5 kV, the signal intensity of the carbamate compound increases with the increase of the voltage, and when the voltage is 3.5-5 kV, the signal intensity of the five analytes to be tested decreases with the increase of the voltage. Preferably, the voltage of the high-voltage power supply is selected to be 3.5 kV.

[0082] According to an embodiment of the present application, the spray desorption solvent is a methanol solution containing (0-1)% formic acid, and the volume of the desorption solvent is 10-30 μL, preferably 20 μL. The inventors have found that when the spray solvent is a methanol solution containing different proportions (0-1%) of formic acid, the extraction amount of the extraction element adsorbed to-be-extracted compounds increases with the increase of the content of formic acid when the content of formic acid is 0-0.1%, and the extraction amount of the extraction element adsorbed to-be-extracted compounds is inhibited to a certain extent with the addition of formic acid when the content of formic acid exceeds 0.1%, and thus the desorption solvent is preferably 0.1% formic acid in methanol. This may be due to the fact that methanol has suitable hydrogen bonding ability, so that it can be more effectively combined with to-be-extracted compounds or extraction elements by hydrogen bonding, thereby hindering the hydrogen bonding between to-be-extracted compounds and extraction elements and facilitating the elution of to-be-extracted compounds from the extraction elements.

[0083] According to an embodiment of the present application, the detection conditions of the mass spectrometer are as follows: detection mode: multiple reaction monitoring (MRM); atomization gas pressure: 55 psi; auxiliary gas pressure: 50 psi; curtain gas pressure: 20 psi; ion source temperature: 550℃; residence time: 100 ms. In this way, the stability, accuracy and sensitivity of the detection are high.

[0084] The present application will be described below with reference to specific examples. It should be noted that these examples are merely illustrative and should not be construed as limiting the scope of the present application.

[0085] The solutions of the present application will be explained below with reference to examples. Those skilled in the art will understand that the following examples are only used to illustrate the present application and should not be regarded as limiting the scope of the present application. If the specific techniques or conditions are not specified in the examples, the techniques or conditions described in the literature in the art or according to the product instructions are used. If the reagents or instruments are not specified by the manufacturer, they are all conventional products that can be purchased, for example, from Sigma Company.

[0086] The materials and reagents used in the embodiments of the present application are shown in Table 1.

[0087]

[0088] Example 1

[0089] The method for preparing the extraction element according to the embodiments of the present application is used to prepare the extraction element with isoprocarb as the to-be-extracted compound, and the preparation is as follows:

[0090] (a) The stainless steel sheet is cut into an isosceles triangle with a base of 1.5 cm and a height of 2 cm.

[0091] (b) The stainless steel sheet was treated with 1 mol / L sulfuric acid for 1 hour under ultrasonic, then washed repeatedly with ultrapure water until neutral, and washed with acetone, and then dried quickly by nitrogen blowing.

[0092] (c) The treated stainless steel sheet was coated with a silicone glue solution with the front side facing up, and then immediately covered with the stainless steel sheet in a glass dish with graphene oxide powder spread on the bottom, and pressure was applied to the back of the stainless steel sheet for 30 seconds. The stainless steel sheet with the surface adhered graphene oxide powder was placed in a constant temperature drying oven and dried at 40°C for 30 minutes. The dried graphene oxide coated stainless steel sheet was placed in methanol and ultrasonicated until no graphene oxide powder fell off, and then dried with nitrogen, thereby obtaining a graphene oxide coating modified steel sheet.

[0093] (d) 1 mmol of isoprocarb (template molecule) and 6 mmol of methacrylic acid (MAA) (functional monomer) were dissolved in 40 mL of a chloroform:methanol (5:1 v / v) mixed solution (porogen), and pre-polymerized at room temperature for 4 hours. Then, 30 mmol of ethylene glycol dimethacrylate (EGDMA) and 100 mg of azobisisobutyronitrile (AIBN) were added to the above solution, and after complete dissolution, the above treated graphene oxide coating modified steel sheet was added, deoxygenated by ultrasonic for 5 minutes, and then sealed under negative pressure in a nitrogen environment by a vacuum pump, and polymerized in a water bath at 65°C for 12 hours.

[0094] (e) The template molecule was removed by repeatedly immersing and eluting with methanol:acetic acid (9.5:0.5 v / v), and after elution, the eluate was washed with pure water until neutral, then washed with methanol, and finally dried with a nitrogen stream, thereby obtaining an extraction element.

[0095] Example 2

[0096] In this example, the extraction element of Example 1 was used to optimize the mass spectrometry detection parameters for carbamate pesticides in river water samples, as follows:

[0097] 1. Experimental method

[0098] (1) Take 15 mL of river water sample in a 50 mL polypropylene centrifuge tube, centrifuge at 8000 r / min at 4°C for 10 min, and collect the supernatant. Filter through a 0.45 µm filter, and take 10 mL as the test solution.

[0099] (2) The carbamate pesticides were enriched and treated to obtain an enrichment, and the specific operation was as follows: take the above test solution, add one piece of extraction element, extract for 20 min at 450 rpm, and then quickly wash the surface with deionized water to remove non-specific co-extractives.

[0100] (3) The extraction element adsorbed with the sample was detected by using a separation-ionization integrated mass spectrometry ionization device. The analysis and detection conditions of the mass spectrometry ionization device included: placing the extraction element on a support frame, adjusting the tip of the extraction element to be in the same straight line with the mass spectrometry inlet, and adjusting the tip of the extraction element to be located at a distance of 5 mm from the mass spectrometry inlet; then, 20 μL of methanol containing 0.1% formic acid was added on the surface of the extraction element, and was left for 10 s; then, a high-voltage power supply was turned on, and a high voltage of +3.5 kV was applied, so that the sample solution moved to the tip of the extraction element, analyte ions were generated at the tip, a spray was formed, and entered the mass spectrometry analysis. An analysis schematic diagram is shown in Figure 2 The mass spectrometry conditions included: detection mode: multiple reaction monitoring (MRM); electrospray voltage (IS): 5500 V; atomization gas pressure (GS1): 55 psi; auxiliary gas pressure (GS2): 50 psi; curtain gas pressure (CUR): 20 psi; ion source temperature (TEM): 550 ℃; residence time (DT): 100 ms.

[0101] 2. Experimental results

[0102] (1) The MRM mass spectrometry parameters of the five kinds of carbamate test substances after optimization are shown in Table 2, and the peak area of the quantitative ion is used as the measurement index.

[0103] Table 2

[0104]

[0105] Note: * is the quantitative ion

[0106] Example 3

[0107] In this embodiment, the enrichment efficiency of the extraction element of the integrated mass spectrometry ionization device on five kinds of carbamate pesticides was evaluated to investigate the enrichment efficiency of the extraction element on the test molecules. A 5-carbamate pesticide (100 ng / mL) mother liquor was prepared, and the sample was detected by using the method of Example 2. The evaluation of the enrichment efficiency was obtained by calculating the enrichment factor (EF). EF is defined as the extraction amount of the extraction element and the blank stainless steel sheet on the same concentration of carbamate pesticide. The peak area of the five kinds of CPs was calculated.

[0108] The EF value results are shown in Table 3. The EF values of CAR, BPMC, CBF, MICP, and PPX were 116.25, 164.95, 70.75, 467.38, and 179.13, respectively. The results showed that the extraction element had excellent enrichment efficiency on carbamate pesticides, which was mainly due to the effect of the functional adsorption layer modified on the surface of the extraction element.

[0109] Table 3

[0110]

[0111] Example 4

[0112] In this embodiment, the influence of extraction condition parameters such as sample solvent, extraction time, sample volume, etc. on the detection results using the integrated mass spectrometry ionization device is studied. Taking the analysis of 5 kinds of carbamate pesticides in simulated biological samples as an example, 5 kinds of carbamate pesticide standard stock solutions (100 ng / mL) are prepared, and the mass spectrometry detection conditions of Example 2 are used for parallel analysis three times.

[0113] 1. Adsorption time study

[0114] Extraction time is an important factor in the extraction process. In order to obtain a better extraction time, the influence of different extraction times 0, 5, 10, 15, 20, 25, 30 min on the extraction amount is studied. The results are shown in Figure 5 Within 0-20 min, as the extraction time increases, the signal intensity of the 5 kinds of CPs also increases; when the extraction time exceeds 20 min, the signal intensity of the analyte remains almost unchanged and does not change significantly, which is mainly due to the dynamic balance between the analyte in the sample solution and the analyte adsorbed on the extraction element. It is proved that the extraction process of the extraction element can be completed in a very short time, which shows that the extraction element has the potential of rapid extraction of analytes. In summary, the extraction time is set to 20 min to ensure a higher adsorption capacity.

[0115] 2. Sample volume study

[0116] The influence of different sample volumes 2, 5, 8, 10, 12, 15 mL on the extraction effect is studied, and three parallel experiments are performed. The experimental results are shown in Figure 6 Within the range of 2-10 mL of sample volume, the signal intensity increases with the increase of sample amount, and when the sample volume continues to increase, the signal intensity no longer changes, which may be due to the fact that too much milk matrix occupies part of the sites of the extraction element, thereby affecting the extraction amount of the analyte. Therefore, 10 mL is selected as the preferred sample volume, which can achieve greater extraction of carbamate pesticides while the interference of the matrix is smaller.

[0117] Figure 7 shows a schematic diagram of the results of the influence of extraction solvents with different pH values according to one embodiment of the present application on 5 kinds of carbamate pesticides; Figure 8 shows a schematic diagram of the results of the influence of extraction solvents with different ionic strengths according to one embodiment of the present application on the extraction of 5 kinds of carbamate pesticides.

[0118] 3. Spray ionization condition study

[0119] The spray ionization conditions determine how much of the target elutes from the extraction element and the signal of the detectable target, which plays an important role in open mass spectrometry analysis. The spray voltage and spray solvent, two experimental parameters, were studied to compare the signal intensity of five CPs analytes to obtain the best spray ionization conditions.

[0120] A. Spray voltage optimization

[0121] The spray voltage has a great influence on the signal of the analyte in open mass spectrometry analysis experiments, so the response of mass spectrometry detection under different voltage conditions was investigated. When the voltage is too low, the analyte that has been eluted by the eluent cannot be ionized, so no signal can be detected within the detection time. However, if the voltage is too high, the spray moves too fast, and the target to be tested cannot be fully ionized, resulting in the instrument being unable to collect all the effective signals. Therefore, 50 ng / mL of a methanol solution of the five CPs was added to the surface of the extraction element, and the signal intensity of the five carbamate pesticides was detected by applying different voltages. Each voltage was detected three times, and the results are shown in Figure 9 As shown, the signal intensity of the five CPs increases with the increase of the applied voltage. When the high voltage increases to 3.5 kV, most of the analytes can obtain the highest signal intensity, and after that, the signal intensity of the analytes decreases with the increase of the voltage. Therefore, in order to obtain stable and high signal intensity for most compounds, +3.5 kV is selected as the preferred voltage.

[0122] B. Spray solvent optimization

[0123] For the spray solvent, not only is it required to maximize the elution of the analytes adsorbed on the extraction element, but it is also required to have higher ionization efficiency for the analytes. In order to obtain higher signal intensity, 100 ng / mL of five carbamate pesticide standards was added to deionized water, and the effect of methanol (MeOH), ethanol (EtOH), and acetonitrile (ACN) as spray solvent on the signal intensity of the five CPs was investigated. The extraction amount was detected by parallel analysis three times. The results are shown in Figure 10 The results show that the elution effect of methanol is the best. Adding 0.1% formic acid, 0.5% formic acid, and 1% formic acid to methanol, the elution ability of methanol containing 0.1% formic acid (FA) for the five CPs is the best. Therefore, methanol containing 0.1% formic acid is selected as the eluent for better effect.

[0124] 5. Methodology verification of mass spectrometry detection

[0125] The standard curve linear range, LODs and LOQs were obtained by detecting 5 different concentrations of the carbamate pesticides in the blank sample matrix. The results are shown in Table 3. The linear range of the 5 test compounds was 1.5-100 ng / mL. The correlation coefficient (r 2 ) was in the range of 0.9900-0.9986. The LODs of the 5 test carbamate pesticides were in the range of 0.11-0.50 ng / mL, and the LOQs were in the range of 0.37-1.67 ng / mL.

[0126] Meanwhile, the recovery rate of the 5 test substances at different added concentrations in the actual sample was investigated. The results are shown in Table 5. The recovery rate was in the range of 80.21%-93.04%, and the SD% value was in the range of 2.61%-7.95%. It was indicated that the detection method of the embodiment of the present application could obtain a good recovery rate, and had a good quantitative ability for trace compounds in the actual sample.

[0127]

[0128] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0129] Although the embodiments of the present application have been shown and described, those skilled in the art can understand that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. An integrated mass spectrometry ionization device for the separation and ionization of carbamate compounds, characterized in that, include: The sample stage includes: Support frame; An extraction element, one end of which is connected to the support frame, the extraction element comprising: A conductive layer, wherein the conductive layer is formed of stainless steel; An extraction layer, located on at least a portion of the surface of the conductive layer, is formed of a molecularly imprinted graphene oxide composite material, wherein the molecular imprinting of the graphene oxide composite material is obtained by polymerization using isopropylcarboxylic acid as a template molecule and methacrylic acid as a functional monomer; and A high-voltage power supply, which is connected to the extraction element. The method for preparing the extraction element includes: Stainless steel sheets are acid-treated to obtain acid-treated steel sheets; Graphene oxide powder is adhered to the acidified steel sheet to obtain a steel sheet with graphene oxide attached. The template molecule, the functional monomer, and the porogen are contacted to undergo a prepolymerization reaction to obtain a prepolymerization solution; and After dissolving the crosslinking agent and initiator in the prepolymerization solution, at least a portion of the steel sheet with attached graphene oxide is immersed in the prepolymerization solution to carry out a polymerization reaction in order to obtain the extraction element. The crosslinking agent is ethylene glycol dimethacrylate. The molar ratio of the template molecule to the monomer and the crosslinking agent is 1:5-7:30-35.

2. The apparatus according to claim 1, characterized in that, The extraction element is in the shape of an isosceles triangle, with the legs of the isosceles triangle having a length of 1.5-2.5 cm and a base of 0.5-1.5 cm.

3. The apparatus according to claim 1, characterized in that, The thickness of the conductive layer is 0.1-0.5 mm.

4. The apparatus according to claim 1, characterized in that, The thickness of the extraction layer is 50-200 μm.

5. The apparatus according to claim 1, characterized in that, The graphene oxide powder is adhered to the acidified steel sheet using a silicone adhesive solution.

6. The apparatus according to claim 1, characterized in that, The initiator is azobisisobutyronitrile.

7. The apparatus according to claim 1, characterized in that, The pore-forming agent is a mixture of chloroform and methanol.

8. The apparatus according to claim 7, characterized in that, The volume ratio of chloroform to methanol is 4-6:

1.

9. The apparatus according to claim 5, characterized in that, The method for preparing the extraction element includes: The stainless steel sheet is immersed in a 1-2 mol / L sulfuric acid solution, ultrasonically treated for 0.5-1.0 hours, rinsed with water until neutral, and then dried with nitrogen to obtain the acidified steel sheet. The acidified steel sheet is coated with the silicone adhesive solution, the graphene oxide powder is adhered to the steel sheet, and it is dried at 40-60°C for 30 minutes. It is then ultrasonically cleaned with methanol to obtain a steel sheet with a graphene oxide coating. The template molecule and the functional monomer are added to the porogen, and the prepolymerization reaction is carried out at room temperature for 2-4 hours to obtain a prepolymerization solution; After the crosslinking agent and the initiator are dissolved in the prepolymerization solution, at least a portion of the steel sheet with graphene oxide attached is immersed in the prepolymerization solution and polymerized at 55-70°C for 12-24 hours in an oxygen-free environment to obtain a preliminary extraction element; and The initial sample of the extraction element is eluted using an elution solution to obtain the extraction element.

10. A mass spectrometer, characterized in that, include: Mass spectrometer detector, the mass spectrometer detector including an inlet; as well as The separation and ionization integrated mass spectrometry ionization device for the detection of carbamate compounds according to any one of claims 1-9, wherein the extraction element of the mass spectrometry ionization device is arranged opposite to the injection port.

11. The mass spectrometer according to claim 10, characterized in that, The apex of the extraction element is positioned opposite the injection port.

12. Use of the integrated mass spectrometry ionization device according to any one of claims 1-9 and the mass spectrometer according to claim 10 or 11 in the detection of carbamate compounds.

13. The use according to claim 12, characterized in that, The carbamate compound is at least one of carbaryl, sec-butylcarbamate, carbofuran, isoprocarb, and propoxur.

14. A method for detecting the content of carbamate compounds in a sample, characterized in that, include: The sample to be tested is brought into contact with the extraction element of the mass spectrometer according to claim 10 or 11 in order to extract the carbamate compounds in the sample to be tested; A spray desorption solvent is dropped onto the surface of the extraction element to desorb the extracted carbamate compound. as well as The desorbed carbamate compounds are ionized using a high-voltage power supply and then detected by a mass spectrometer to obtain the content of carbamate compounds in the sample.

15. The method according to claim 14, characterized in that, The extraction was carried out with shaking at 450 rpm for 5-30 minutes.

16. The method according to claim 15, characterized in that, The extraction time was 20 minutes.

17. The method according to claim 14, characterized in that, The volume of the sample to be tested is 2-15 mL.

18. The method according to claim 17, characterized in that, The volume of the sample to be tested is 10 mL.

19. The method according to claim 14, characterized in that, The distance between the tip of the extraction element and the inlet of the mass spectrometer detector is 3-8 mm.

20. The method according to claim 19, characterized in that, The distance between the tip of the extraction element and the inlet of the mass spectrometer detector is 5 mm.

21. The method according to claim 14, characterized in that, The mass ionization conditions of the integrated mass spectrometry ionization device are as follows: the spray voltage of the high-voltage power supply is 2.5-5kV.

22. The method according to claim 21, characterized in that, The mass ionization conditions of the integrated mass spectrometry ionization device are as follows: the spray voltage of the high-voltage power supply is 3.5kV.

23. The method according to claim 14, characterized in that, The spray desorption solvent is a methanol solution containing (0-1)% formic acid, and the volume of the spray desorption solvent is 10-30 μL.

24. The method according to claim 23, characterized in that, The volume of the spray desorption solvent is 20 μL.

25. The method according to claim 14, characterized in that, The detection conditions of the mass spectrometer detector are as follows: Detection method: Multiple reaction monitoring (MRM); Nebulizer gas pressure: 55 psi; Auxiliary gas pressure: 50 psi; Air curtain pressure: 20 psi; Ion source temperature: 550℃; Dwell time: 100ms.

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