CN112326812A - Method for simultaneously detecting five pesticides in underground water by isotope dilution-ONLINESPE-HRMS - Google Patents
Method for simultaneously detecting five pesticides in underground water by isotope dilution-ONLINESPE-HRMS Download PDFInfo
- Publication number
- CN112326812A CN112326812A CN202011047591.XA CN202011047591A CN112326812A CN 112326812 A CN112326812 A CN 112326812A CN 202011047591 A CN202011047591 A CN 202011047591A CN 112326812 A CN112326812 A CN 112326812A
- Authority
- CN
- China
- Prior art keywords
- sample
- phase extraction
- water
- water sample
- column
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
- G01N30/04—Preparation or injection of sample to be analysed
- G01N30/06—Preparation
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
- G01N30/04—Preparation or injection of sample to be analysed
- G01N30/06—Preparation
- G01N30/08—Preparation using an enricher
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
- G01N30/04—Preparation or injection of sample to be analysed
- G01N30/06—Preparation
- G01N30/14—Preparation by elimination of some components
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
- G01N30/26—Conditioning of the fluid carrier; Flow patterns
- G01N30/28—Control of physical parameters of the fluid carrier
- G01N30/34—Control of physical parameters of the fluid carrier of fluid composition, e.g. gradient
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
- G01N30/62—Detectors specially adapted therefor
- G01N30/72—Mass spectrometers
- G01N30/7233—Mass spectrometers interfaced to liquid or supercritical fluid chromatograph
- G01N30/724—Nebulising, aerosol formation or ionisation
- G01N30/7266—Nebulising, aerosol formation or ionisation by electric field, e.g. electrospray
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
- G01N30/86—Signal analysis
- G01N30/8658—Optimising operation parameters
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
- G01N30/86—Signal analysis
- G01N30/8675—Evaluation, i.e. decoding of the signal into analytical information
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
- G01N30/04—Preparation or injection of sample to be analysed
- G01N2030/042—Standards
- G01N2030/045—Standards internal
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
- G01N30/04—Preparation or injection of sample to be analysed
- G01N30/06—Preparation
- G01N2030/062—Preparation extracting sample from raw material
Landscapes
- Chemical & Material Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Health & Medical Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Engineering & Computer Science (AREA)
- Library & Information Science (AREA)
- Dispersion Chemistry (AREA)
- Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
Abstract
The invention provides a method for analyzing five pesticides in underground water by isotope dilution-Online SPE-HRMS, wherein a water sample is filtered by a 0.45 mu m glass fiber filter membrane to remove suspended impurities, and a filtered water sample is taken to be 10.0mL to a large-volume sample bottle. The water sample is automatically enriched and purified by an online solid phase extraction column. The water sample enrichment solvent is one thousandth of formic acid water, and the purification solvent is 6 percent of methanol and 94 percent of formic acid water. Through 6 leading to 2 position valve switching, five kinds of target object that await measuring are eluted to the analytical column, and the elution solvent is acetonitrile and thousandth formic acid water. And meanwhile, the method adopts an isotope internal standard method for quantification. The method is applied to the analysis of groundwater samples, and the carbofuran is detected in part of samples through detection, wherein the detected concentration is 2.33-12.33 ng/L.
Description
Technical Field
The invention relates to a water sample detection method for underground water, in particular to a method for simultaneously detecting five pesticides in underground water by isotope dilution, Online solid phase extraction and liquid chromatography high-resolution mass spectrometry (Online SPE-HRMS).
Background
China is a big country for agricultural production, and with the increasing demand of grains and other agricultural products, a large number of different kinds of pesticides are used for preventing and treating plant diseases and insect pests in order to improve the crop yield. During the application process, pesticides are easy to enter different areas such as underground water, surface water and soil, and cause pollution, and the environmental problems of the pesticides are attracted by people. Five pesticides, namely pentachlorophenol, 2,4, 6-trichlorophenol, 2, 4-D, carbofuran and dimethylcarbofuran, belong to high-efficiency and broad-spectrum bactericides, insecticides and herbicides, and the pesticides have large use amount and wide use range in agricultural production in China. Pentachlorophenol and 2,4, 6-trichlorophenol widely exist in water environment, are chlorophenols with wide application range, can be used as bactericides, insecticides, wood preservatives and the like, and are prioritized to control pollutants by the national general environmental protection administration of China due to strong toxicity, three-cause effect, wide pollution range and difficult degradation. Aldicarb and carbofuran are broad-spectrum carbamates bactericides, have the advantages of easy degradation, short residual period, low toxicity and the like, and are widely used in agricultural production of grains, vegetables and the like. 2, 4-D is a class of chlorophenoxy carboxylic acid herbicides with larger use amount in China, and is mainly used for preventing and controlling the weeding growth of monocotyledons in fields such as wheat, corn, sorghum and the like due to low price, high efficiency, low toxicity and the like.
At present, in domestic and foreign documents, methods for detecting the five pesticides in water mainly comprise various methods such as a high performance liquid chromatography, a gas chromatography-mass spectrometry combined method, a liquid chromatography-mass spectrometry combined method and the like, wherein GC and GC-MS need derivatization, and the process is complex and time-consuming. Liquid chromatography-mass spectrometry is often used. However, in multi-residue analysis, low resolution mass spectrometry has certain limitations in high throughput detection due to low resolution, slow scanning speed, and the like. A novel quadrupole/electrostatic field ion Orbitrap high-resolution mass spectrometer (UPLC/Q Orbitrap) developed in recent years has the resolution as high as 280000, and the accurate mass number can be obtained through one-stage scanning, and the relative mass deviation is 1-10 multiplied by 10-6The method has good qualitative and quantitative analysis capability and has obvious advantages in trace compound detection analysis and screening confirmation.
The underground water is an important drinking and industrial and agricultural water resource for human beings, so that the establishment of the method for analyzing the pesticide residue in the underground water has important scientific significance. At present, related researches are carried out on methods for analyzing pesticide residues in underground water, methods such as liquid-liquid extraction, accelerated solvent extraction and solid-phase extraction are mostly adopted, the traditional pretreatment methods are complex and time-consuming, and the quantitative detection is mostly carried out by adopting an external standard method or a general internal standard method. For quantification by an external standard method, the accuracy is easily influenced by factors such as instrument conditions and matrix effects. Internal standard quantitation, in general, is somewhat unsatisfactory for multicomponent quantitation and is also susceptible to a variety of factors. The Isotope Dilution (ID) is an internationally recognized stoichiometric method in which an Isotope of a target substance to be measured is added to a solution before sample treatment, and the concentration of the target substance to be measured is quantitatively determined by using the change in the ratio of the isotopes. Compared with the traditional quantification method, the method can accurately quantify, makes up for the defects of an external standard method or a common internal standard method to a certain extent, and improves the accuracy and reliability of a quantification result.
For the five pesticides, HJ 744-2015 gas chromatography mass spectrometry for determination of water quality phenolic compounds is recommended in underground water quality standards of pentachlorophenol and 2,4, 6-trichlorophenol, and GB/T23214-2008 liquid chromatography tandem mass spectrometry for determination of residual amounts of pesticides and related chemicals in drinking water is recommended in 2, 4-D, carbofuran and dichloroformat, and no report is found on the simultaneous automatic analysis method for the five pesticide residues.
Disclosure of Invention
Aiming at the defect that five pesticide residues are not detected simultaneously in the prior art, the research adopts an isotope technology combined with online solid-phase extraction to establish an ultra-high performance liquid chromatography-tandem mass spectrometry method for detecting five pesticides in underground water simultaneously, and the specific scheme is as follows:
the invention provides a method for simultaneously detecting five pesticides in underground water by isotope dilution-Online SPE-HRMS, wherein the five pesticides are pentachlorophenol, 2,4, 6-trichlorophenol, 2, 4-D, carbofuran and dichlorcarb, and the method comprises the following steps:
1) groundwater sample pretreatment method
Standing a water sample, taking supernatant, filtering through a 0.45-micron glass fiber filter membrane to remove suspended impurities, accurately measuring 10mL of the water sample, filtering, adding 10 muL of isotope internal standard mixed solution, shaking uniformly, swirling for 1min, transferring the water sample to a 10mL sample feeding bottle, and feeding the sample into a machine for analysis;
the isotope internal standard mixed solution is pentachlorophenol-13C. 2,4, 6-trichlorophenol-13C. 2, 4-D3Carbofuran-d3Aldicarb-d3The concentration of the five isotope internal standards is 100 ng/mL;
2) enrichment, purification and elution separation methods:
comprises two flow paths for automatic enrichment purification and elution separation respectively, wherein the first flow path: pumping the water sample from the sample injection bottle, pumping the water sample to an online solid phase extraction column by using a thousandth formic acid aqueous solution for enrichment, wherein 2.5mL of water sample is pumped every time, the water sample is pumped for 3 times, and the volume of the water sample is pumped for 7.5mL in total, so that the enrichment is completed; and then flushing the online solid-phase extraction column with a mixed solution of 94% thousandth of formic acid and 6% of methanol for five minutes to complete purification, switching to a 2-position valve after purification is completed, flushing the online solid-phase extraction column with 100% of methanol through a first flow path to complete regeneration of the online solid-phase extraction column, and then changing a mobile phase back to 100% thousandth of formic acid water to balance the online solid-phase extraction column. A second flow path: before valve switching, an equilibrium chromatographic column is used, after valve switching, a target substance enriched on an online solid phase extraction column is eluted to the chromatographic column by a certain gradient for separation, the specific elution gradient is 5-6min, and a mobile phase keeps 10% of methanol and 90% of thousandth of formic acid; 6-11min, the methanol is increased from 10% to 70%; 11-12min, increasing the proportion of methanol from 70% to 100%, keeping for 8min, reducing the proportion of methanol to 10%, keeping for 6.6min, and waiting for the next injection;
3) analysis with Preset Mass Spectrometry conditions
Wherein the mass spectrum conditions are as follows:
an ion source: an electrospray heating ion source; a mass analyzer: an ion trap mass analyser (Orbitrap); ion source temperature: at 450 ℃; ion transport metal capillary temperature: 320 ℃; spraying voltage: 4.0 kV; lens voltage: 55 kV; flow rate of sheath gas: 55arb, assist gas flow rate: 15 arb; scanning mode: FullMS-ddMS 2; the collection range is as follows: m/z is 100-1000; the primary full-scan resolution is 70000 FWHM; c-trap maximum capacity (ACGtarget): 3 × 106; c-trap maximum injection time 100 ms; data dependent secondary daughter ion full scan (dd-MS2) resolution: 17500 FWHM; c-trap maximum capacity (ACGtarget)1 × 105; c-trap maximum injection time 50 ms; normalized Collision Energy (NCEs): 50 eV; and (3) dynamic exclusion: 10 s; column temperature: at 40 ℃.
Further, the size of the on-line solid phase extraction column is 50mm multiplied by 0.5mm and 60 mu m; the size of the column was 2.1X 100mm, 3.0. mu.m.
Further, the preparation of the isotope internal standard mixed solution: and (3) preparing five isotope internal standards which correspond to the target object one by taking methanol as diluent, wherein the concentration is 100ng/mL, and after the preparation is finished, storing at-4 ℃.
Further, before step 3), the method further comprises: preparing a mixed standard working solution: 10, 20, 50, 100, 150 and 200 mu L of mixed standard stock solution and 10 mu L of isotope internal standard mixed solution are respectively transferred to 10.0mL of ultrapure water five pesticides to prepare 10, 20, 50, 100, 150 and 200ng/L mixed standard working solution which is prepared for use.
Further, the mixed standard stock solution contains five substances of pentachlorophenol, 2,4, 6-trichlorophenol, 2, 4-D, carbofuran and aldicarb, and the concentration is 10 ng/mL.
Compared with the traditional offline solid-phase extraction-liquid mass spectrometry method, the method has the advantages of high automation degree, greenness, safety, rapidness, accuracy and the like, the sample does not need complicated manual concentration and enrichment, rapid and automatic analysis is realized by directly feeding samples, the ultrahigh resolution of the electrostatic field ion orbit trap high-resolution mass spectrometry and the accurate mass number which can be obtained are combined, the matrix interference can be reduced to the maximum extent, the detection accuracy is improved, the false positive is reduced, a new technology is provided for qualitative and quantitative detection of pesticide residues in the underground water, and the method has strong practical and economic values.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a schematic diagram of on-line vortex solid phase extraction-liquid chromatography-mass spectrometry;
FIG. 2 is an extracted ion diagram of five standard solutions;
FIG. 3 is a comparison of peak areas for 5 polar pesticides at different pH;
FIG. 4 is a graph of the extracted ion flow and first and second mass spectra of carbofuran in a sample.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
1, the method comprises the following steps:
the invention provides a method for simultaneously detecting five pesticides in underground water by isotope dilution-Online SPE-HRMS, wherein the five pesticides are pentachlorophenol, 2,4, 6-trichlorophenol, 2, 4-D, carbofuran and dichlorcarb, and the method comprises the following steps:
1) groundwater sample pretreatment method
Standing a water sample, taking supernatant, filtering through a 0.45-micron glass fiber filter membrane to remove suspended impurities, accurately measuring 10mL of the water sample, filtering, adding 10 muL of isotope internal standard mixed solution, shaking uniformly, swirling for 1min, transferring the water sample to a 10mL sample feeding bottle, and feeding the sample into a machine for analysis;
the isotope internal standard mixed solution is pentachlorophenol-13C. 2,4, 6-trichlorophenol-13C. 2, 4-D3Carbofuran-d3Aldicarb-d3The concentration of the five isotope internal standards is 100 ng/mL;
2) enrichment, purification and elution separation methods:
comprises two flow paths for automatic enrichment purification and elution separation respectively, wherein the first flow path: pumping the water sample from the sample injection bottle, pumping the water sample to an online solid phase extraction column by using a thousandth formic acid aqueous solution for enrichment, wherein 2.5mL of water sample is pumped every time, the water sample is pumped for 3 times, and the volume of the water sample is pumped for 7.5mL in total, so that the enrichment is completed; and then flushing the online solid-phase extraction column with a mixed solution of 94% thousandth of formic acid and 6% of methanol for five minutes to complete purification, switching to a 2-position valve after purification is completed, flushing the online solid-phase extraction column with 100% of methanol through a first flow path to complete regeneration of the online solid-phase extraction column, and then changing a mobile phase back to 100% thousandth of formic acid water to balance the online solid-phase extraction column. A second flow path: before valve switching, an equilibrium chromatographic column is used, after valve switching, a target substance enriched on an online solid phase extraction column is eluted to the chromatographic column by a certain gradient for separation, the specific elution gradient is 5-6min, and a mobile phase keeps 10% of methanol and 90% of thousandth of formic acid; 6-11min, the methanol is increased from 10% to 70%; 11-12min, the proportion of the methanol is increased from 70 to 100 percent and kept for 8min, and then the methanol is reduced to 10 percent and kept for 6.6min to wait for the next injection. 3) And (4) analyzing by using preset mass spectrum conditions.
2 experimental part
2.1 reagents and materials
Reagent: acetonitrile (chromatographic grade, Phillipsburg USA), methanol (chromatographic grade, Phillipsburg USA), formic acid (chromatographic grade, Dikma Technology INC USA), ultrapure water made by Milli-Q system (Millipore, Germany), other reagents were all analytical.
And (3) standard substance: 2, 4-D (GBW (E)060552), 2,4, 6-trichlorophenol (GBW (E)080473), carbofuran (GBW (E)060225), aldicarb (GBW (E)082611) and pentachlorophenol (GBW (E)080475) are available from the Chinese institute of metrology science. 2, 4-D3Aldicarb-d from FirstStandard, China3Carbofuran- d 32,4, 6-trichlorophenol-13C. Pentachlorophenol-13C was purchased from TRC, canada.
2.2 instrumentation
UltiMateTM3000 double ternary system component (Thermo Fisher Scientific, usa): the WPS-3000TSL autosampler is equipped with a 2.5mL large-volume sample ring, the TCC-3200 column incubator is equipped with a six-way valve switching device, a DGP 3600M double-ternary gradient pump and an SRD 3600 solvent rack (with a vacuum degasser), a Q experimental plus quadrupole/electrostatic field orbitrap high-resolution mass spectrometer (Thermo Fisher, USA), a vortex oscillator (Shanghai Qingpu Shanghai West instruments), and a Milli-Q ultra-pure water device (Advantage-10/Elix, Millipore, USA).
2.3 preparation of Standard solution
Isotope internal standard mixed solution: five internal standards of 100 mug/mL and the target object in one-to-one correspondence are prepared into a mixed standard solution of 1.0 mug/mL by using methanol as a diluent, and the mixed standard solution is diluted to an isotope internal standard mixed solution of 100ng/mL, and after the preparation is finished, the mixed standard solution is placed at-4 ℃ for storage.
Mixing standard working solution: preparing a 1.0 mu g/mL mixed standard solution from five 100 mu g/mL pesticide standard solutions by using methanol as a diluent, diluting step by step to obtain a 10.0ng/mL mixed standard stock solution, respectively sucking 10, 20, 50, 100, 150, 200 mu L of the 10.0ng/mL mixed standard stock solution and 10 mu L of 100ng/mL isotope internal standard mixed solution to 10.0mL ultrapure water, preparing 10, 20, 50, 100, 150 and 200ng/L mixed standard working solutions, and preparing the mixed standard working solutions for use at present.
2.4 sample pretreatment
Standing a water sample, taking supernatant, filtering through a 0.45 mu m glass fiber filter membrane to remove suspended impurities, accurately measuring 10mL of the water sample, filtering, adding 10 mu L of isotope internal standard mixed solution, shaking uniformly, swirling for 1min, transferring the water sample to a 10mL sampling bottle, and feeding the bottle for analysis.
2.5 conditions of instrumental analysis
Automated on-line solid phase extraction and analysis: the autosampler aspirates 2.5mL of water sample each time, the sample was automatically enriched on an on-line solid phase extraction column (Turbolow cycle (50 mm. times.0.5 mm, 60 μm) Thermo Fisher Scientific) under high flow rate of mobile phase ( pump 1, 100% formic acid solution (1:1000, V/V)), and the aspiration of the enriched sample was repeated three times for a total sample volume of 7.5 mL. After the water sample is automatically enriched, the flow rate of a left pump is reduced to 0.50mL/min, the flow phase ratio is unchanged, and the online solid-phase extraction column is cleaned for 5.0 min. The six-way valve was then switched to position 2, at which time the right pump mobile phase (60% formic acid solution, 40% acetonitrile) backwash off the target and into an analytical column (Acclaim PolarAdvantag II C18(PA2) (2.1X 100mm, 3.0 μm), Thermo Fisher Scientific) with an elution time of 7.0 min. After the back elution is finished, the six-way valve is switched back to the No. 1 position, and the pump 1 mobile phase is kept for 10.0min at 4.0ml/min and 95% acetonitrile for on-line solid phase extraction column regeneration. The pump 2 flow path completes liquid phase separation and mass spectrum detection, and the pump 2 separation gradient program is as follows: and (3) 0.0-6.0 min of 10% acetonitrile, then increasing the proportion of the acetonitrile to 70% within 5min, and further increasing the proportion to 100% within 1min and keeping the proportion for 6 min. Finally, the mobile phase returns to the initial condition to wait for the next injection. The on-line solid phase extraction liquid chromatography-mass spectrometry system is shown in figure 1.
Automatic enrichment purification and elution separation, and an online solid phase extraction column: turbolow Cyclone (50 mm. times.0.5 mm, 60 μm); left pump mobile phase: a is 0.1% formic acid water; b is methanol, a chromatographic separation column: acclaimTMPolar Advantage II C18(PA2) (2.1X 100mm, 3.0 μm); right pump mobile phase: a is 0.1% formic acid water; b is acetonitrile, with a specific gradientThe elution procedure is shown in table 1.
TABLE 1 Online solid phase extraction gradient elution procedure
Table 1 The online SPE-UHPLC-MS/MS gradient elution and valve switching programs
Mass spectrum conditions: an ion source: an electrospray heated ion source (HESI); a mass analyzer: an ion trap mass analyser (Orbitrap); ion source temperature: at 450 ℃; ion transport metal capillary temperature: 320 ℃; spraying voltage: 4.0 kV; lens voltage: 55 kV; flow rate of sheath gas: 55arb, auxiliary gas: 15 arb; scanning mode: full MS-ddMS 2; the collection range is as follows: m/z is 100-1000; the primary full-scan resolution is 70000 FWHM; c-trap maximum capacity (ACG target): 3X 106(ii) a C-trap maximum injection time 100 ms; data dependent secondary daughter ion full scan (dd-MS2) resolution: 17500 FWHM; c-trap maximum capacity (ACG target) 1X 105(ii) a C-trap maximum injection time 50 ms; normalized Collision Energy (NCEs): 50 eV; and (3) dynamic exclusion: 10 s; column temperature: at 40 ℃.
3 results and discussion
3.1 selection of Mass Spectrometry conditions
An electrospray heating ion source (HESI) is adopted, due to the ionization property difference of a target object to be detected, mass spectrum acquisition is carried out in a primary mass spectrum full-scanning mode in a set acquisition range (100-1000m/z)) by adopting a positive and negative simultaneous scanning mode, quantification is carried out through the chromatographic peak area obtained by extracting the accurate mass number of parent ions in a target list, and qualitative determination is carried out through secondary ion obtained by automatic triggering and retention time. For high resolution mass spectrometry, mass accuracy is one of the important factors influencing qualitative and quantitative accuracy, and as the measured actual mass number is closer to the theoretical mass number, the relative mass deviation between the measured actual mass number and the theoretical mass number is smaller, and the accuracy is higher[15-16]. As shown in Table 2, the relative mass deviation of each pesticide is less than 1.8X 10-6The mass accuracy error conforming to the high-resolution mass spectrometry is 5.0 multiplied by 10-6And (4) requiring. Therefore, it is advantageousThe accurate mass number obtained by the method is used for carrying out qualitative and quantitative analysis on the target compound.
TABLE 2 Mass Spectrometry method parameters for five pesticides
Table 2 The optimized MRM parameters for tandem mass spectrometry
3.2 liquid chromatography and on-line solid phase extraction column selection
In this experiment, acetonitrile-thousandth of formic acid aqueous solution is selected as an eluent, and the separation effects of three chromatographic columns of Thermo Accucore aQ (2.1X 150mm, 2.6 μm), Acclaim PA2(100mm X2.1 mm,3 μm) and Waters acquity BEH C18(100mm X2.1 mm,1.7 μm) on a target compound are compared. Under respective optimal separation conditions, the target compound is retained by the three chromatographic columns, but the pentachlorophenol and the 2,4, 6-trichlorophenol do not generate peaks when the C18 column is separated; and meanwhile, the column pressure connected with the online SPE column is very high and exceeds a column pressure set threshold value. The peak of the AQ column and the peak of the PA2 column are generated by the five substances, but the peak type of the PA2 column is good, the response is high, and the peak does not have the phenomena of forking and tail shedding. Meanwhile, in order to obtain a better separation effect, the baseline separation of the target object is effectively ensured by combining solid-phase extraction and gradient elution. A methanol-thousandth formic acid aqueous solution is selected as a sample solution, and two online solid phase extraction columns of Cyclone and Cyclone-P are compared, so that the phenomenon that the polarity of the Cyclone-P column is strengthened, the enrichment capacity on a target substance is strong, and the peak broadening phenomenon is caused after elution is found. For this purpose, the on-line solid phase extraction column was a Cyclone column (50 mm. times.0.5 mm, 60 μm) and the chromatography column was Acclaim PA2(150 mm. times.3.0 mm,3 μm). For the separation of the five compounds, a gradient elution procedure was chosen, and all compounds were able to be separated well within 26.5 min. The extracted ion profiles of the five standard solutions are shown in figure 2.
3.3 Online optimization of solid phase extraction conditions
The on-line solid phase extraction can be divided into three processes of sample loading, cleaning and regeneration, and for the sample loading process, the flow rate is a key factor for controlling the retention of a target compound in an SPE column, so that the target compound can obtain a higher peak area and a relatively stable result by comparing target compound responses under different sample loading flow rates of 2 mL/min, 3 mL/min, 4mL/min and 5mL/min in the research.
In addition, the cleaning time was optimized, the mobile phase conditions (6% MeOH) and the loading rate (0.5mL/min) were maintained, and the response values of the target compounds were compared at 1.0min,2.0min,5.0min, and 6.0min, and when the cleaning time was 6.0min, the response values of the five target compounds were rapidly decreased. For this reason, the optimum cleaning conditions were 6% MeOH for 5.0 min. Meanwhile, the change of the response intensity of the target substance under different elution times of 3.0, 4.0, 5.0, 7.0, 8.0 and 9.0min is also considered in the regeneration process. The result shows that the complete elution of the target object can be realized when the elution time is 7.0 min.
3.4 pH optimization of water sample
The target object to be detected in the underground water is determined by on-line solid phase extraction, the pretreatment is simple, and after suspended impurities are removed, the internal standard is added, so that the on-machine analysis can be carried out. Although the pretreatment method is simple, factors influencing the extraction effect need to be considered when establishing the solid phase extraction method. For underground water, the matrix is relatively simple, and the influence factors include the pH value of a water sample, suspended particles, experimental operation and the like. Meanwhile, researches on pesticides show that some pesticides are easy to hydrolyze under alkaline conditions and change in properties under acidic conditions. Therefore, the pH value of the water sample needs to be optimized to investigate the influence of the water sample on the target object under different pH conditions. The results are shown in FIG. 3, and it can be seen from FIG. 3 that: the peak areas of the five pesticides change along with the change of the pH value of a water sample, when the pH value of the water sample is 7.0, other targets except 2, 4-D can obtain higher peak areas and stable results, and when the pH value of the solution is continuously increased, the peak area of each target is reduced and rapidly reduced. Therefore, the pH of the selected water sample was 7.0.
3.5 applicability of Online vortex solid phase extraction to groundwater media
The matrix of the groundwater sample is relatively simple, the selected packing of the online vortex solid phase extraction column is characterized by combining the retention characteristics of size exclusion and reverse phase chromatography, and because the size of the packing particles is large (60 mu m), the sample is in a turbulent flow state under a high flow speed state, potential macromolecular matrix and other suspended particles, impurities and the like in the sample can be removed, and small molecules are retained. Therefore, the effect of the online vortex solid-phase extraction column on the removal of the underground water sample matrix is examined through continuous sample injection. Through simulation experiments, under the optimal conditions, the sample injection amount is 7.5mL, and the sample injection is repeated (n is 5), so that the column pressure is not obviously changed. Therefore, under the optimal condition, the online vortex solid phase extraction column can effectively remove the matrix in the groundwater and can be repeatedly used. Meanwhile, the analysis and detection of the batch groundwater samples show that the column pressure of nearly 1000 groups of samples rises by only 200 psi.
3.6 method Linear Range, recovery and detection limits
Pure methanol is adopted to prepare a series of mixed standard working solutions with concentration gradients, and the mixed standard working solutions are quantified by an isotope internal standard method and are measured under optimized conditions. And (3) drawing a standard curve by taking the chromatographic peak area of the target characteristic ion as a vertical coordinate and the concentration (ng/L) of the corresponding working solution as a horizontal coordinate, wherein the target is in good linearity within the concentration range of 10-200 ng/L, and the correlation coefficients (R) are all larger than 0.9950. The standard solution of the analyte is added to the negative sample without the component to be detected, the concentration corresponding to 3-fold signal-to-noise ratio (S/N-3) is defined as a method detection Limit (LOD), the concentration corresponding to 10-fold signal-to-noise ratio (S/N-10) is defined as a quantification Limit (LOQ), and the result shows that the detection limit (S/N-3) is between 0.5 and 10ng/L, and the quantification limit (S/N-10) is between 1.0ng/L and 10 ng/L. In addition, the standard addition experiment is also carried out in a blank sample, and when the standard addition concentration level is respectively 10ng/mL and 100ng/mL, the recovery rate is between 90.0% and 110%, the relative standard deviation is between 3.1% and 8.9% (n is 5), and the accuracy and precision meet the relevant requirements.
3.7 actual sample detection
The method established by the experiment is applied to detection and analysis of actual underground water samples, underground water sampled or checked at ordinary times in a laboratory is measured, and 19 water samples are detected together. As a result, carbofuran pollution exists in part of water samples, and the content range of the carbofuran pollution is 2.33-12.33 ng/L. The flow chart and the first-order and second-order mass spectrograms of the extracted carbofuran in a certain sample are shown in figure 4.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (6)
1. A method for simultaneously detecting five pesticides in underground water by isotope dilution-Online SPE-HRMS is characterized by comprising the following steps of:
1) groundwater sample pretreatment method
Standing a water sample, taking supernatant, filtering through a 0.45-micron glass fiber filter membrane to remove suspended impurities, accurately measuring 10mL of the water sample, filtering, adding 10 muL of isotope internal standard mixed solution, shaking uniformly, swirling for 1min, transferring the water sample to a 10mL sample feeding bottle, and feeding the sample into a machine for analysis;
the isotope internal standard mixed solution is pentachlorophenol-13C. 2,4, 6-trichlorophenol-13C. 2, 4-D3Carbofuran-d3Aldicarb-d3The concentration of the five isotope internal standards is 100 ng/mL;
2) enrichment, purification and elution separation methods:
comprises two flow paths for automatic enrichment purification and elution separation respectively, wherein the first flow path: pumping the water sample from the sample injection bottle, pumping the water sample to an online solid phase extraction column by using a thousandth formic acid aqueous solution for enrichment, wherein 2.5mL of water sample is pumped every time, the water sample is pumped for 3 times, and the volume of the water sample is pumped for 7.5mL in total, so that the enrichment is completed; washing the online solid-phase extraction column with a mixed solution of 94% thousandth of formic acid and 6% of methanol for five minutes to complete purification, switching to a 2-position valve after purification is completed, washing the online solid-phase extraction column with 100% of methanol in a first flow path to complete regeneration of the online solid-phase extraction column, and setting a rear mobile phase as 100% thousandth of formic acid water to balance the online solid-phase extraction column; a second flow path: before valve switching, an equilibrium chromatographic column is used, after valve switching, a target substance enriched on an online solid phase extraction column is eluted to the chromatographic column by a certain gradient for separation, the specific elution gradient is 5-6min, and a mobile phase keeps 10% of methanol and 90% of thousandth of formic acid; 6-11min, the methanol is increased from 10% to 70%; 11-12min, increasing the proportion of methanol from 70% to 100%, keeping for 8min, reducing the proportion of methanol to 10%, keeping for 6.6min, and waiting for the next injection;
3) analysis with Preset Mass Spectrometry conditions
Wherein the mass spectrum conditions are as follows: an ion source: an electrospray heating ion source; a mass analyzer: an ion trap mass analyser (Orbitrap); ion source temperature: at 450 ℃; ion transport metal capillary temperature: 320 ℃; spraying voltage: 4.0 kV; lens voltage: 55 kV; flow rate of sheath gas: 55arb, assist gas flow rate: 15 arb; scanning mode: FullMS-ddMS2(ii) a The collection range is as follows: m/z is 100-1000; the primary full-scan resolution is 70000 FWHM; c-trap maximum capacity (ACGtarget): 3X 106(ii) a C-trap maximum injection time 100 ms; data dependent secondary ion full scan (dd-MS)2) Resolution ratio: 17500 FWHM; c-trap maximum capacity (ACGtarget) 1X 105(ii) a C-trap maximum injection time 50 ms; normalized Collision Energy (NCEs): 50 eV; and (3) dynamic exclusion: 10 s; column temperature: at 40 ℃.
2. The method of claim 1, wherein the in-line solid phase extraction column has dimensions of 50mm x 0.5mm, 60 μm; the size of the column was 2.1X 100mm, 3.0. mu.m.
3. The method of claim 2, wherein the on-line solid phase extraction column is a polymer packing, the chromatographic column packing is a polymer with enhanced polarity, the polarity of the chromatographic column is slightly stronger than that of the on-line solid phase extraction column, and the peak shape of the target is ensured by the polarity matching of the two packing types, so that the analysis accuracy is improved.
4. The method according to one of claims 1 to 3, characterized in that the preparation of the isotopic internal standard mixed solution: five isotope internal standards which are in one-to-one correspondence with the target object and prepared by taking methanol as diluent comprise pentachlorophenol-13C. 2,4, 6-trichlorophenol-13C. 2, 4-D3Carbofuran-d3Aldicarb-d3Mixing the solutions at a concentration of 100ng/mL, and storing at-4 deg.C after preparation.
5. The method according to one of claims 1 to 4, further comprising, before step 3): preparing a mixed standard working solution: 10, 20, 50, 100, 150 and 200 mu L of mixed standard stock solution and 10.0 mu L of isotope internal standard mixed solution are respectively transferred to 10.0mL of ultrapure water to prepare 10, 20, 50, 100, 150 and 200ng/L of mixed standard working solution which is prepared for use at present.
6. The method of claim 5, wherein the mixed standard stock solution contains pentachlorophenol, 2,4, 6-trichlorophenol, 2, 4-D, carbofuran and aldicarb, and the concentration is 10.0 ng/mL.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011047591.XA CN112326812A (en) | 2020-09-29 | 2020-09-29 | Method for simultaneously detecting five pesticides in underground water by isotope dilution-ONLINESPE-HRMS |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011047591.XA CN112326812A (en) | 2020-09-29 | 2020-09-29 | Method for simultaneously detecting five pesticides in underground water by isotope dilution-ONLINESPE-HRMS |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112326812A true CN112326812A (en) | 2021-02-05 |
Family
ID=74312972
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011047591.XA Pending CN112326812A (en) | 2020-09-29 | 2020-09-29 | Method for simultaneously detecting five pesticides in underground water by isotope dilution-ONLINESPE-HRMS |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112326812A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113588832A (en) * | 2021-04-25 | 2021-11-02 | 山东省物化探勘查院 | Method for simultaneously measuring atrazine, 2, 4-dichlorophenoxyacetic acid, carbofuran and aldicarb in water body |
| CN114509492A (en) * | 2022-01-27 | 2022-05-17 | 国家地质实验测试中心 | Isotope dating method for graphite Re-Os |
| CN115166101A (en) * | 2022-08-04 | 2022-10-11 | 南京理工大学 | Comprehensive screening method for comprehensively identifying new pollutants in water sample |
| CN116087374A (en) * | 2023-04-11 | 2023-05-09 | 农业农村部环境保护科研监测所 | Detection method for trace bisphenol compounds in agricultural products |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110824077A (en) * | 2019-11-14 | 2020-02-21 | 云南中烟工业有限责任公司 | System and method for measuring NNK and metabolites thereof by liquid-liquid two-dimensional chromatography based on solid-phase extraction |
-
2020
- 2020-09-29 CN CN202011047591.XA patent/CN112326812A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110824077A (en) * | 2019-11-14 | 2020-02-21 | 云南中烟工业有限责任公司 | System and method for measuring NNK and metabolites thereof by liquid-liquid two-dimensional chromatography based on solid-phase extraction |
Non-Patent Citations (1)
| Title |
|---|
| XIANG-TING TU ET AL.: "Fully automated identification and quantification of five polar pesticides in groundwater by isotope dilution-online solid phase extraction coupled with high-performance liquid chromatography-quadrupole Orbitrap high-resolution mass spectrometry", 《J MASS SPECTROM.》 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113588832A (en) * | 2021-04-25 | 2021-11-02 | 山东省物化探勘查院 | Method for simultaneously measuring atrazine, 2, 4-dichlorophenoxyacetic acid, carbofuran and aldicarb in water body |
| CN114509492A (en) * | 2022-01-27 | 2022-05-17 | 国家地质实验测试中心 | Isotope dating method for graphite Re-Os |
| CN115166101A (en) * | 2022-08-04 | 2022-10-11 | 南京理工大学 | Comprehensive screening method for comprehensively identifying new pollutants in water sample |
| CN116087374A (en) * | 2023-04-11 | 2023-05-09 | 农业农村部环境保护科研监测所 | Detection method for trace bisphenol compounds in agricultural products |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112326812A (en) | Method for simultaneously detecting five pesticides in underground water by isotope dilution-ONLINESPE-HRMS | |
| CN106124678B (en) | The quick screening method of perfluorochemical and its precursor substance in the flesh of fish | |
| CN110954608A (en) | Liquid chromatography-tandem mass spectrometry determination method for perfluoroalkyl alcohol in textile | |
| CN105259287A (en) | Second-order mass spectrometric detection method for bisphenol substances in water environment | |
| CN113702558A (en) | Method for detecting trace estrogen substances in water environment | |
| CN111965287A (en) | Method for determining 5 nitrophenol compounds in soil based on ultrahigh pressure high performance liquid chromatography tandem mass spectrometry | |
| CN105784858B (en) | Method for measuring PPCPs in environmental soil | |
| CN113295797A (en) | Method for rapidly detecting ethyl carbamate in white spirit based on ultra-high performance liquid chromatography combined high-resolution mass spectrometry | |
| CN107941950B (en) | Method for simultaneously determining nine functional components in different parts of Changshan grapefruit by ultra-high performance liquid chromatography-tandem mass spectrometry | |
| CN111413432A (en) | Method for detecting trace PFOA (perfluorooctanoic acid) in fluorine-containing polymer emulsion product | |
| CN113155991B (en) | Method for rapidly determining sulfonamide antibiotics in water by full-automatic online extraction ultra-high performance liquid chromatography-tandem mass spectrometry | |
| CN111220722B (en) | Method for simultaneously determining 8 p-hydroxybenzoate compounds in soil | |
| CN111122715B (en) | Method for simultaneously determining contents of various trace anions in sodium carboxymethylcellulose by using ion chromatography | |
| CN105334282B (en) | Co-detecting method for environmental estrogens in surface water body | |
| Guo et al. | An automatic and sensitive method for simultaneous determination of sixteen polycyclic aromatic hydrocarbons and four derivatives by online solid-phase extraction coupled with ultra-high performance liquid chromatography with online solvent filtration | |
| CN115980211A (en) | Kit and method for quantitatively detecting 25-hydroxyvitamin D and application thereof | |
| CN115326994A (en) | Method and system for simultaneously analyzing multi-class smoke exposure biomarkers and using method | |
| CN111257461B (en) | Detection method for triazine herbicide and degradation product thereof in seawater | |
| CN111239277B (en) | Method and kit for determining N-dimethyl nitrosamine in water and application | |
| CN113655147A (en) | Method for detecting microcystin in water | |
| CN113533570A (en) | Analysis method for main metabolites of organophosphorus flame retardant in sediment | |
| CN110161169B (en) | Method for rapidly detecting multiple drug active substances in water environment | |
| CN113820421A (en) | Method for measuring 6 phenolic compounds in water | |
| CN112526030A (en) | Method for analyzing diallyl trisulfide in food industry wastewater | |
| CN110554097A (en) | method for measuring residual quantity of 7-aminocephalosporanic acid in water and wastewater |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20210205 |
|
| WD01 | Invention patent application deemed withdrawn after publication |