Canping Pan

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Name: 潘灿平; Pan, CanPing

Organization: China Agricultural University , China

Department: Department of Applied Chemistry

Title: Professor(PhD)

TOPICS

Analytical Chemistry

Material Chemistry

Carbon Nanotubes

Applied Chemistry

herbicide Pesticide

Chemicals
References

Analysis of sulfonamides, tilmicosin and avermectins residues in typical animal matrices with multi-plug filtration cleanup by liquid chromatography–tandem mass spectrometry detection

Co-reporter:Yuhong Qin, Freedom Jatamunua, Jingru Zhang, Yanjie Li, Yongtao Han, Nan Zou, Jihao Shan, Yanbin Jiang, Canping Pan

Journal of Chromatography B 2017 Volume 1053(Volume 1053) pp:

Publication Date(Web):15 May 2017

DOI:10.1016/j.jchromb.2017.04.006

•A veterinary drugs multi-residue method in animal samples was developed.•Modified QuEChERS and ultrasound-assisted extraction were optimized.•M-PFC method with n-Hexane delipidation were used for cleanup.•Solvents, ultrasonic process, sorbents, m-PFC procedure were optimized.The frequent use of various veterinary drugs could lead to residue bioaccumulation in animal tissues, which could cause dietary risks to human health. In order to quickly analyze the residues, a liquid chromatography tandem mass spectrometry (LC–MS/MS) method was developed for detecting Sulfonamides, Tilmicosin and Avermectins (AVMs) residues in animal samples. For sample preparation, modified QuEChERS (quick, easy, cheap, effective, rugged and safe) and ultrasound-assisted extraction (UAE) methods were used. For sample cleanup, n-Hexane delipidation and multi-plug filtration cleanup (m-PFC) method based on primary-secondary amine (PSA) and octadecyl-silica (C18) were used, followed by LC–MS/MS analysis. It was validated on 7 animal matrices (bovine, caprine, swine meat and their kidneys, milk) at two fortified concentration levels of 5 and 100 μg/kg. The recoveries ranged from 82 to 107% for all analytes with relative standard deviations (RSDs) less than 15%. Matrix-matched calibrations were performed with coefficients of determination above 0.998 for all analytes within concentration levels of 5–500 μg/kg. The developed method was successfully used to analysis veterinary drugs of real animal samples from local markets.

Automated multi-filtration cleanup with nitrogen-enriched activated carbon material as pesticide multi-residue analysis method in representative crop commodities

Co-reporter:Yuhong Qin, Jingru Zhang, Yifan Li, Qiuxiao Wang, Yangliu Wu, Lanshu Xu, Xiaojuan Jin, Canping Pan

Journal of Chromatography A 2017 Volume 1515(Volume 1515) pp:

Publication Date(Web):15 September 2017

DOI:10.1016/j.chroma.2017.08.009

•General automated pesticide multi-residue analysis methods were developed.•Methods were developed on six representative crop commodities.•The method was achieved by injecting extracts through the sorbents automatically.•Nitrogen-enriched activated carbon showed excellent adsorption ability.An automated multi-filtration cleanup (Auto m-FC) method with nitrogen-enriched activated carbon material based on modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) extracts was developed. It was applied to pesticide multi-residue analysis in six representative crop commodities. The automatic device was aimed to improve the cleanup efficiency and reduce manual operation workload in cleanup step. By controlling extracts volume, flow rate and Auto m-FC cycles, the device could finish cleanup process accurately. In this work, nitrogen-enriched activated carbon mixed with alternative sorbents and anhydrous magnesium sulfate (MgSO4) was packed in a column for Auto m-FC and followed by liquid chromatography with tandem mass spectrometric (LC–MS/MS) detection. This newly developed carbon material showed excellent cleanup performance. It was validated by analyzing 23 pesticides in six representative matrices spiked at two concentration levels of 10 and 100 μg/kg. Water addition volume, salts, sorbents, Auto m-FC procedure including the flow rate and the Auto m-FC cycles for each matrix were optimized. Then, three general Auto m-FC methods were introduced to high water content, high oil and starch content, difficult commodities. Spike recoveries were within 82 and 106% and 1–14% RSD for all analytes in the tested matrices. Matrix-matched calibrations were performed with the coefficients of determination over 0.997 between concentration levels of 10 and 1000 μg/kg. The developed method was successfully applied to the determination of pesticide residues in market samples.

Study on Mobility, Distribution and Rapid Ion Mobility Spectrometry Detection of Seven Pesticide Residues in Cucumber, Apple, and Cherry Tomato

Co-reporter:Nan Zou, Chunhao Yuan, Ronghua Chen, Juan Yang, Yifan Li, Xuesheng Li, and Canping Pan

Journal of Agricultural and Food Chemistry 2017 Volume 65(Issue 1) pp:

Publication Date(Web):December 12, 2016

DOI:10.1021/acs.jafc.6b03084

This research explores the mobility and distribution rules of simazine, acetamiprid, hexazinone, paclobutrazol, amitraz, clofentezine, and boscalid in the pulp and peel of apple, cucumber, and cherry tomato. A laboratory test was carried out by treating the matrices with standard solution for different periods of time. The percentage sorption of pesticides ranged from 0.02 to 89.3% for the three matrices. The pesticides’ distribution was also determined, and all pesticides showed ratio values (Q) between pulp and peel concentrations in the three matrices of <0.8, which proved that the highest pesticides’ content was found in the peel. In addition, a rapid and simple process combining a surface swab capture method and pulse glow discharge–ion mobility spectrometry (PGD-IMS) detection was established for the detection of pesticides on matrix surfaces. In the swab method, the whole matrix surface was swabbed manually by swab sticks, and swab sticks were agitated in acetonitrile to release the pesticides. The releasing factors of pesticides in the three matrices were calculated. The linearity, LOD, LOQ, and matrix effect were investigated to assess the applicability of the swab-IMS process in practical analysis. The swab-IMS method is rapid, sensitive, and quantitative and can be achieved in the field.Keywords: distribution; ion mobility spectrometry; mobility; pesticides; residue; surface swab;

Coupling of multi-walled carbon nanotubes/polydimethylsiloxane coated stir bar sorptive extraction with pulse glow discharge-ion mobility spectrometry for analysis of triazine herbicides in water and soil samples

Co-reporter:Nan Zou, Chunhao Yuan, Shaowen Liu, Yongtao Han, Yanjie Li, Jialei Zhang, Xiang Xu, Xuesheng Li, Canping Pan

Journal of Chromatography A 2016 Volume 1457() pp:14-21

Publication Date(Web):29 July 2016

DOI:10.1016/j.chroma.2016.06.043

•A method based on SBSE coupled with PGD-IMS was developed for analysis of triazine pesticide residues.•An injection port with sealing device and stir bars hold device were designed, making desorption and detection of analytes proceeded simultaneously.•Mixture of MWCNTs and PDMS were shown to be effective in enriching the triazines.•The SBSE-PGD-IMS method was environmentally friendly without organic solvent consumption in the entire experimental procedures.•The proposed method was applied for the analysis of real ground water, surface water and soil samples.An analytical method based on stir bar sorptive extraction (SBSE) coupled with pulse glow discharge-ion mobility spectrometry (PGD-IMS) was developed for analysis of three triazine pesticide residues in water and soil samples. An injection port with sealing device and stir bars hold device were designed and constructed to directly position the SBSE fiber including the extracted samples into the heating device, making desorption and detection of analytes proceeded simultaneously. The extraction conditions such as SBSE solid phase material, extraction time, extraction temperature, pH value and salt concentration were optimized. Mixture of MWCNTs-COOH and PDMS were shown to be effective in enriching the triazines. The LODs and LOQs of three triazines were found to be 0.006–0.015 μg kg−1 and 0.02–0.05 μg kg−1, and the linear range was 0.05–10 μg L−1 with determination coefficients from 0.9987 to 0.9993. The SBSE-PGD-IMS method was environmentally friendly without organic solvent consumption in the entire experimental procedures, and it was demonstrated to be a commendable rapid analysis technique for analysis of triazine pesticide residues in environmental samples on site. The proposed method was applied for the analysis of real ground water, surface water and soil samples.

Residue levels of five grain-storage-use insecticides during the production process of sorghum distilled spirits

Co-reporter:Yongtao Han, Baoyong Huang, Shaowen Liu, Nan Zou, Juan Yang, Zezhi Zhong, Xuesong Zhang, Le Song, Yuhong Qin, Canping Pan

Food Chemistry 2016 Volume 206() pp:12-17

Publication Date(Web):1 September 2016

DOI:10.1016/j.foodchem.2016.03.035

•Residue level of five insecticides during distilled spirits production was assessed.•Soaking process obviously reduced dichlorvos residue with 87% decrease.•Fermentation removed pesticide residues by 40–63% due to biological degradation.•Distillation process was proved to be effective for reducing pesticide residues.•The PFs of five insecticides were clarified in the production of distilled spirits.Residue levels of dichlorvos, fenitrothion, pirimiphos-methyl, malathion and deltamethrin during sorghum distilled spirits production were examined. The analytical method for these pesticides in sorghum, fermented sorghum, rice hull and distilled spirits was validated through linearity, matrix effect, accuracy and precision, limit of quantification (LOQ) and limit of detection (LOD) parameters. The pesticide residue levels before/after each process of soaking, steaming, fermentation, and distillation were determined by gas chromatography coupled with tandem mass spectrometry (GC–MS/MS). Results showed that soaking process could obviously reduce dichlorvos residue with 87% decrease as its high vapor pressure. The steaming process reduced pesticide residues by 42–83% mainly due to evaporation or thermal degradation. Also, the fermentation could remove pesticide residues by 40–63% in favor of biological degradation. Moreover, the distillation process was proved to be effective for decreasing the pesticide residues in distilled spirits with the processing factors lower than other processes for each pesticide.

Residue determination of glufosinate in plant origin foods using modified Quick Polar Pesticides (QuPPe) method and liquid chromatography coupled with tandem mass spectrometry

Co-reporter:Yongtao Han, Le Song, Pengyue Zhao, Yanjie Li, Nan Zou, Yuhong Qin, Xuesheng Li, Canping Pan

Food Chemistry 2016 Volume 197(Part A) pp:730-736

Publication Date(Web):15 April 2016

DOI:10.1016/j.foodchem.2015.11.021

•Modified QuPPe method was used for extraction of glufosinate in selected matrices.•MWCNTs was used for the purification of the extract, much better than PSA.•The sample extract was derivatized with 10 g/L FMOC-Cl at 40 °C for an hour.•Glufosinate-FMOC was detected by LC–MS/MS.A sensitive and specific method for the determination of glufosinate in plant origin foods was developed. The method involves extraction using modified QuPPe method, clean-up by multi-walled carbon nanotubes (MWCNTs), derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl) and detection with liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS). The method was validated on twelve matrices spiked at 10 or 20, 100 and 500 μg/kg. The recovery ranged from 80% to 108% with intra-day RSDs (n = 5) of 0.6–9.8% and inter-day RSDs (n = 15) of 3.0–9.4%. Good linearities (R2 ⩾ 0.9991) were obtained for all matrices. The limit of detection (LOD) and limit of quantification (LOQ) for the selected matrices ranged from 0.3 to 3.3 μg kg−1 and from 1 to 10 μg kg−1, respectively. The method was demonstrated to be reliable and sensitive for the routine monitoring of glufosinate in plant origin foods.

Automated multi-plug filtration cleanup for liquid chromatographic–tandem mass spectrometric pesticide multi-residue analysis in representative crop commodities

Co-reporter:Yuhong Qin, Jingru Zhang, Yuan Zhang, Fangbing Li, Yongtao Han, Nan Zou, Haowei Xu, Meiyuan Qian, Canping Pan

Journal of Chromatography A 2016 Volume 1462() pp:19-26

Publication Date(Web):2 September 2016

DOI:10.1016/j.chroma.2016.07.073

•Automated m-PFC method for pesticide multi-residue analysis was developed.•Salts, sorbents, m-PFC procedure, automated volume and speed were optimized.•General methods for common and complex matrices were developed.•The suggested methods were expected to be applied to other commodities.An automated multi-plug filtration cleanup (m-PFC) method on modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) extracts was developed. The automatic device was aimed to reduce labor-consuming manual operation workload in the cleanup steps. It could control the volume and the speed of pulling and pushing cycles accurately. In this work, m-PFC was based on multi-walled carbon nanotubes (MWCNTs) mixed with other sorbents and anhydrous magnesium sulfate (MgSO4) in a packed tip for analysis of pesticide multi-residues in crop commodities followed by liquid chromatography with tandem mass spectrometric (LC–MS/MS) detection. It was validated by analyzing 25 pesticides in six representative matrices spiked at two concentration levels of 10 and 100 μg/kg. Salts, sorbents, m-PFC procedure, automated pulling and pushing volume, automated pulling speed, and pushing speed for each matrix were optimized. After optimization, two general automated m-PFC methods were introduced to relatively simple (apple, citrus fruit, peanut) and relatively complex (spinach, leek, green tea) matrices. Spike recoveries were within 83 and 108% and 1–14% RSD for most analytes in the tested matrices. Matrix-matched calibrations were performed with the coefficients of determination >0.997 between concentration levels of 10 and 1000 μg/kg. The developed method was successfully applied to the determination of pesticide residues in market samples.

Multiresidue Method for Determination of 183 Pesticide Residues in Leeks by Rapid Multiplug Filtration Cleanup and Gas Chromatography–Tandem Mass Spectrometry

Co-reporter:Nan Zou, Yongtao Han, Yanjie Li, Yuhong Qin, Kejia Gu, Jingru Zhang, Canping Pan, and Xuesheng Li

Journal of Agricultural and Food Chemistry 2016 Volume 64(Issue 31) pp:6061-6070

Publication Date(Web):December 11, 2015

DOI:10.1021/acs.jafc.5b05132

This study reports the development of a novel multiplug filtration cleanup (m-PFC) procedure for analysis of pesticide residues in leek samples followed by gas chromatography–tandem mass spectrometry detection. The leek samples were initially purified following the dispersive solid-phase extraction with different sorbents to determine the most suitable proportioning of sorbent materials; then, the m-PFC method was carried out by applying the streamlined procedure with syringes. Average recoveries of most pesticides were in the range from 70.2 to 126.0% with the relative standard deviation < 20% with the m-PFC process. The limits of detection were 0.03–3.3 μg kg–1. The limits of quantification were 0.1–10 μg kg–1. The m-PFC process is convenient and time-efficient, taking just a few seconds per sample. Finally, the developed method was successfully applied to the determination of pesticide residues in market samples. In that analysis, 35 pesticides were detected in 29 samples, with values ranging from 2.0 to 9353.1 μg kg–1.Keywords: d-SPE; leek; m-PFC; MWCNTs; pesticide residue analysis;

Automated Multiplug Filtration Cleanup for Pesticide Residue Analyses in Kiwi Fruit (Actinidia chinensis) and Kiwi Juice by Gas Chromatography–Mass Spectrometry

Co-reporter:Yuhong Qin, Jingru Zhang, Yining He, Yongtao Han, Nan Zou, Yanjie Li, Ronghua Chen, Xuesheng Li, and Canping Pan

Journal of Agricultural and Food Chemistry 2016 Volume 64(Issue 31) pp:6082-6090

Publication Date(Web):January 26, 2016

DOI:10.1021/acs.jafc.5b06027

To reduce labor-consuming manual operation workload in the cleanup steps, an automated multiplug filtration cleanup (m-PFC) method for QuEChERS (quick, easy, cheap, effective, rugged, and safe) extracts was developed. It could control the volume and speed of pulling and pushing cycles accurately. In this study, m-PFC was based on multiwalled carbon nanotubes (MWCNTs) mixed with primary–secondary amines (PSA) and anhydrous magnesium sulfate (MgSO4) in a packed column for analysis of pesticide residues followed by gas chromatography–mass spectrometry (GC-MS) detection. It was validated by analyzing 33 pesticides in kiwi fruit and kiwi juice matrices spiked at two concentration levels of 10 and 100 μg/kg. Salts, sorbents, m-PFC procedure, 4 mL of automated pulling and pushing volume, 6 mL/min automated pulling speed, and 8 mL/min pushing speed were optimized for each matrix. After optimization, spike recoveries were within 71–120% and <20% RSD for all analytes in kiwi fruit and kiwi juice. Matrix-matched calibrations were performed with the coefficients of determination >0.99 between concentration levels of 10 and 1000 μg/kg. The developed method was successfully applied to the determination of pesticide residues in market samples.Keywords: automated; kiwi fruit and kiwi juice; m-PFC; MWCNTs; pesticide multiresidue analysis;

Rapid analysis of pesticide residues in drinking water samples by dispersive solid-phase extraction based on multiwalled carbon nanotubes and pulse glow discharge ion source ion mobility spectrometry

Co-reporter:Nan Zou;Kejia Gu;Shaowen Liu;Yanbing Hou;Jialei Zhang;Xiang Xu;Xuesheng Li

Journal of Separation Science 2016 Volume 39( Issue 6) pp:1202-1212

Publication Date(Web):

DOI:10.1002/jssc.201501258

An analytical method based on dispersive solid-phase extraction with a multiwalled carbon nanotubes sorbent coupled with positive pulse glow discharge ion mobility spectrometry was developed for analysis of 30 pesticide residues in drinking water samples. Reduced ion mobilities and the mass–mobility correlation of 30 pesticides were measured. The pesticides were divided into five groups to verify the separation capability of pulse glow discharge in mobility spectrometry. The extraction conditions such as desorption solvent, ionic strength, conditions of adsorption and desorption, the amounts of multiwalled carbon nanotubes, and solution pH were optimized. The enrichment factors of pesticides were 5.4- to 48.7-fold (theoretical enrichment factor was 50-fold). The detection limits of pesticides were 0.01∼0.77 μg/kg. The linear range was 0.005–0.2 mg/L for pesticide standard solutions, with determination coefficients from 0.9616 to 0.9999. The method was applied for the analysis of practical and spiked drinking water samples. All results were confirmed by high-performance liquid chromatography with tandem mass spectrometry. The proposed method was proven to be a commendably rapid screening qualitative and semiquantitative technique for the analysis of pesticide residues in drinking water samples on site.

Analytical method for 44 pesticide residues in spinach using multi-plug-filtration cleanup based on multiwalled carbon nanotubes with liquid chromatography and tandem mass spectrometry detection

Co-reporter:Yuhong Qin;Baoyong Huang;Jingru Zhang;Yongtao Han;Yanjie Li;Nan Zou;Jianguo Yang

Journal of Separation Science 2016 Volume 39( Issue 9) pp:1757-1765

Publication Date(Web):

DOI:10.1002/jssc.201501401

Spinach is one of the most commonly planted vegetables worldwide. A high chlorophyll content makes spinach a complicated matrix in pesticide residue analysis. In this study, a rapid clean-up method was developed for the analysis of pesticide multi-residues in spinach followed by liquid chromatography with tandem mass spectrometry. A modified QuEChERS method with multiwalled carbon nanotubes and carbon material was adopted in the multi-Plug Filtration Cleanup procedure. This method was validated for 44 representative pesticides spiked at two concentration levels of 10 and 100 μg/kg. The pesticides of different physicochemical properties were registered on spinach in China. The recoveries were between 76 and 114% for major pesticides with relative standard deviations of less than 15%, except for quizalofop-P-ethyl, pyrimethanil, and carbendazim. Matrix-matched calibration curves were performed with the coefficients of determination higher than 0.995 for the studied pesticides for concentration levels of 10–500 μg/kg. The limits of quantitation ranged from 2 to 10 μg/kg. The developed method was successfully applied to determine pesticide residues in Chinese market spinach samples.

Multiplug filtration cleanup method with multi-walled carbon nanotubes for the analysis of malachite green, diethylstilbestrol residues, and their metabolites in aquatic products by liquid chromatography–tandem mass spectrometry

Co-reporter:Yuhong Qin;Jingru Zhang;Yanjie Li;Yongtao Han

Analytical and Bioanalytical Chemistry 2016 Volume 408( Issue 21) pp:5801-5809

Publication Date(Web):2016 August

DOI:10.1007/s00216-016-9686-6

The food safety supervision in aquatic products has raised public concern in recent years. In this study, a liquid chromatographic–tandem mass spectrometric (LC-MS/MS) method for the simultaneous quantification and identification of four residues of the ever widely used analytes (including malachite green, leucomalachite green, diethylstilbestrol, and dienestrol) in aquaculture samples was developed. For sample preparation, a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) method was used, which was initially developed for pesticide residue analysis. For cleanup procedure, low-temperature cleanup method was combined with multiplug filtration cleanup (m-PFC) method based on multi-walled carbon nanotubes (MWCNTs). The volume of water, extraction solvent, cleanup sorbents, and m-PFC procedure were optimized for carp, striped bass, and giant salamander matrices. It was validated by analyzing four residues in each matrix spiked at three concentration levels of 0.5, 5, and 50 μg/kg (n = 5). The method was successfully validated according to the 2002/657/EC guidelines. After optimization, spike recoveries were within 73–106 % and <15 % relative standard deviations (RSDs) for all analytes in the tested matrices. Limits of quantification (LOQs) for the proposed method ranged from 0.10 to 0.50 μg/kg. Matrix-matched calibrations were performed with the coefficients of determination >0.998 between concentration levels of 0.5 and 200 μg/kg. The developed method was successfully applied to the determination of residues in market samples.

Multi-residue determination of 171 pesticides in cowpea using modified QuEChERS method with multi-walled carbon nanotubes as reversed-dispersive solid-phase extraction materials

Co-reporter:Yongtao Han, Le Song, Nan Zou, Ronghua Chen, Yuhong Qin, Canping Pan

Journal of Chromatography B 2016 Volume 1031() pp:99-108

Publication Date(Web):15 September 2016

DOI:10.1016/j.jchromb.2016.07.043

•Modified QuEChERS method was used to extract 171 pesticides in cowpea samples.•MWCNTs was used to clean up the cowpea matrices containing a lot of pigments.•The clean-up effect of MWCNTs was obviously superior to GCB and PSA.•The method was successfully applied to monitor pesticide residues in cowpea samples.A rapid and sensitive method for the determination of 171 pesticides in cowpea was developed using multi-walled carbon nanotubes (MWCNTs) as reversed-dispersive solid-phase (r-DSPE) extraction materials. The clean-up performance of MWCNTs was proved to be obviously superior to PSA and GCB. This method was validated on cowpea spiked at 0.01 and 0.1 mg kg−1 with five replicates. The mean recoveries for 169 pesticides ranged from 74% to 129% with relative standard deviations (RSDs) (n = 5) lower than 16.4%, except diflufenican and quizalofop-ethyl. Good linearity for all pesticides was obtained with the calibration curve coefficients (R2) larger than 0.9970. The limit of detection (LODs) and limit of quantification (LOQs) for the 171 pesticides ranged from 0.001 to 0.003 mg kg−1 and from 0.002 to 0.009 mg kg−1, respectively. The method was demonstrated to be reliable and sensitive for the routine monitoring of the 171 pesticides in cowpea samples.

The comparison of dispersive solid phase extraction and multi-plug filtration cleanup method based on multi-walled carbon nanotubes for pesticides multi-residue analysis by liquid chromatography tandem mass spectrometry

Co-reporter:Yuhong Qin, Pengyue Zhao, Sufang Fan, Yongtao Han, Yanjie Li, Nan Zou, Shuangyu Song, Yuan Zhang, Fangbing Li, Xuesheng Li, Canping Pan

Journal of Chromatography A 2015 Volume 1385() pp:1-11

Publication Date(Web):13 March 2015

DOI:10.1016/j.chroma.2015.01.066

•Comparison the cleanup performance of d-SPE and m-PFC on pesticide multiresidue analysis.•Improved previous m-PFC columns to simplify the equipment.•M-PFC had more stable recoveries and lower RSDs.•M-PFC method reduced matrix interferences and had less matrix effects.•M-PFC is a rapid and high-throughput cleanup method on analysis of pesticides.In this study, dispersive-Solid Phase Extraction (d-SPE) cleanup and multi-plug filtration cleanup (m-PFC) methods were compared for 25 representative pesticides in six matrices (wheat, spinach, carrot, apple, citrus and peanut) by QuEChERS-LC-ESI-MS/MS detection. The type of sorbents in dispersive-SPE (d-SPE) was optimized for the above matrices. Multi-walled carbon nanotubes (MWCNTs), which mixed other materials like PSA (Primary Secondary Amines), GCB (Graphitized Carbon Black) and C18 (Octadecyl-silica), showed brilliant cleanup performance in multi residue monitoring (MRM) pesticide residue analysis. Cleanup effects with d-SPE and m-PFC methods were examined. When spiked at 3 concentration levels of 10, 100, 500 μg/kg in above matrices, for both d-SPE and m-PFC methods, the recoveries ranged from 70 to 110% with relative standard deviations (RSDs) lower than 20%. Limits of quantification (LOQs) for both cleanup methods ranged from 1 to 25 μg/kg. Matrix-matched calibrations were performed with the coefficients of determination more than 0.99 between concentration levels of 10–1000 μg/kg. It was found that m-PFC was more convenient and effective than d-SPE with the same sorbents, due to the increased contact time and contact area between the extracts and compressed sorbents. The study demonstrated that m-PFC method could be used as a rapid, convenient and high-throughput cleanup method for analysis of pesticide residues.

Simultaneous determination of 70 pesticide residues in leek, leaf lettuce and garland chrysanthemum using modified QuEChERS method with multi-walled carbon nanotubes as reversed-dispersive solid-phase extraction materials

Co-reporter:Yongtao Han, Nan Zou, Le Song, Yanjie Li, Yuhong Qin, Shaowen Liu, Xuesheng Li, Canping Pan

Journal of Chromatography B 2015 Volume 1005() pp:56-64

Publication Date(Web):15 November 2015

DOI:10.1016/j.jchromb.2015.10.002

•Leek, leaf lettuce and garland chrysanthemum are troublesome vegetables.•Modified QuEChERS method was used to extract 70 pesticides in troublesome matrices.•MWCNTs was used to clean up the troublesome matrices containing a lot of pigments.•The clean-up effect of MWCNTs was obviously superior to GCB and PSA.•The method was successfully applied to monitor pesticide residues in market samples.Leek, leaf lettuce and garland chrysanthemum are troublesome vegetables containing large amount of pigments which may bring serious matrix interferences in mass spectrometry analysis. Multi-walled carbon nanotubes (MWCNTs) have a good effect for the cleanup of troublesome matrix. So the study was designed to develop a multi-residue method for the determination of 70 pesticide residues in leek, leaf lettuce and garland chrysanthemum based on a modified QuEChERS procedure using MWCNTs as reversed-dispersive solid phase extraction (r-DSPE) materials to remove the interferences of pigments. PSA and GCB were used as comparison. LC–MS/MS was used to identify and quantify the residue levels of multi-pesticides. The clean-up performance of MWCNTs was demonstrated to be obviously superior to GCB and PSA. This method was validated on leek, leaf lettuce and garland chrysanthemum spiked at the concentration of 10, 50 and 100 μg kg−1 with five replicates. The recoveries of 70 pesticides ranged from 74% to 119%, with relative standard deviations (RSDs) lower than 14.2%. Good linearity (R2 ≥ 0.9903) was obtained at the range of 10–1000 μg/L for all pesticides in the selected matrices. The limit of quantification (LOQs) and limit of detection (LODs) of the 70 pesticides for the selected matrices ranged from 0.3 to 7.9 μg kg−1 and from 0.1 to 2.4 μg kg−1 respectively. The method was successfully applied to the routine monitoring of pesticide residues in market samples.

Rapid Multiplug Filtration Cleanup with Multiple-Walled Carbon Nanotubes and Gas Chromatography–Triple-Quadruple Mass Spectrometry Detection for 186 Pesticide Residues in Tomato and Tomato Products

Co-reporter:Pengyue Zhao, Baoyong Huang, Yanjie Li, Yongtao Han, Nan Zou, Kejia Gu, Xuesheng Li, and Canping Pan

Journal of Agricultural and Food Chemistry 2014 Volume 62(Issue 17) pp:3710-3725

Publication Date(Web):February 10, 2014

DOI:10.1021/jf405240j

This study reports the development and validation of a novel rapid cleanup method based on multiple-walled carbon nanotubes in a packed column filtration procedure for analysis of pesticide residues followed by gas chromatography–triple-quadruple tandem mass spectrometry detection. The cleanup method was carried out by applying the streamlined procedure on a multiplug filtration cleanup column with syringes. The sorbent used for removing the interferences in the matrices is multiple-walled carbon nanotubes mixed with anhydrous magnesium sulfate. The proposed cleanup method is convenient and time-saving as it does not require any solvent evaporation, vortex, or centrifugation procedures. It was validated on 186 pesticides and 3 tomato product matrices spiked at two concentration levels of 10 and 100 μg kg–1. Satisfactory recoveries and relative standard deviations are shown for most pesticides using the multiplug filtration cleanup method in tomato product samples. The developed method was successfully applied to the determination of pesticide residues in market samples.

Spinach or Amaranth Contains Highest Residue of Metalaxyl, Fluazifop-P-butyl, Chlorpyrifos, and Lambda-cyhalothrin on Six Leaf Vegetables upon Open Field Application

Co-reporter:Sufang Fan, Fengzu Zhang, Kailin Deng, Chuanshan Yu, Shaowen Liu, Pengyue Zhao, and Canping Pan

Journal of Agricultural and Food Chemistry 2013 Volume 61(Issue 9) pp:2039-2044

Publication Date(Web):February 6, 2013

DOI:10.1021/jf304710u

To select representative leaf vegetables which may contain the highest residue, field experiments of metalaxyl, fluazifop-P-butyl, chlorpyrifos, and lambda-cyhalothrin on six crops including pakchoi, rape, crown daisy, amaranth, spinach, and lettuce were designed and conducted. In this study, a high-performance liquid chromatograph and electrospray ionization tandem mass spectrometer with multiple reaction monitoring was used to simultaneously determine metalaxyl and fluazifop-P-butyl residue in various samples, and a gas chromatograph with electron capture detector was used to detect chlorpyrifos and lambda-cyhalothrin. The limits of quantification (LOQ) of metalaxyl, fluazifop-P-butyl, chlorpyrifos, and lambda-cyhalothrin were in the range of 0.001–0.01 mg kg–1 for all samples, and the average recoveries of all pesticides ranged from 67.6 to 119.1% at spiked levels of 0.01–0.1 mg kg–1. In supervised field trials, the half-lives of metalaxyl, fluazifop-P-butyl, chlorpyrifos, and lambda-cyhalothrin were in the range of 1.11–3.79 days, 1.11–2.27 days, 1.13–5.17 days, and 1.77–6.24 days. It was also found that all pesticide residues in spinach and/or amaranth were higher than others after application. It is recommended that spinach or amaranth can be selected as a representative crop of leaf vegetables in studying systemic fungicide, insecticides, and herbicides with similarity as metalaxyl, fluazifop-P-butyl, chlorpyrifos, and lambda-cyhalothrin.

Influence of Different Planting Seasons of Six Leaf Vegetables on Residues of Five Pesticides

Co-reporter:Sufang Fan, Kailin Deng, Chuanshan Yu, Pengyue Zhao, Aijuan Bai, Yanjie Li, Canping Pan, and Xuesheng Li

Journal of Agricultural and Food Chemistry 2013 Volume 61(Issue 38) pp:9036-9044

Publication Date(Web):August 26, 2013

DOI:10.1021/jf4029078

To investigate the influence of different planting seasons on the dissipation of pesticides, field experiments of thiophanate-methyl, metalaxyl, fluazifop-P-butyl, chlorpyrifos, and λ-cyhalothrin on six crops including pakchoi, rape, crown daisy, amaranth, spinach, and lettuce were designed and conducted. In this study, a high-performance liquid chromatography and electrospray ionization–tandem mass spectrometer with multiple reaction monitoring was used to simultaneously determine thiophanate-methyl and its metabolite carbendazim, metalaxyl, and fluazifop-P-butyl in various samples; gas chromatography with an electron capture detector was used to detect chlorpyrifos and λ-cyhalothrin. The limits of quantitation (LOQs) of these six pesticides were in the range of 0.001–0.01 mg kg–1 for all samples, and the average recoveries of all pesticides ranged from 60.1 to 119.1% at 0.01 and 0.1 mg kg–1 spiked levels. The relative standard deviation (RSD) ranged from 1.1 to 13.9%. All maximal concentrations of the six pesticides in six leaf vegetables in autumn were higher than in summer in Beijing. For most pesticides half-lives in autumn were longer than in summer. The results showed that the initial concentration, maximal concentration, and half-lives of pesticides were influenced not only by environmental factors such as light, heat, moisture, and rainy climate but also by plant matrices.

Multiplug filtration clean-up with multiwalled carbon nanotubes in the analysis of pesticide residues using LCESI-MS/MS

Co-reporter:Pengyue Zhao;Sufang Fan;Chuanshan Yu;Junyan Zhang

Journal of Separation Science 2013 Volume 36( Issue 20) pp:3379-3386

Publication Date(Web):

DOI:10.1002/jssc.201300411

A novel design for a rapid clean-up method was developed for the analysis of pesticide residues in fruit and vegetables followed by LC–ESI-MS/MS. The acetonitrile-based sample extraction technique was used to obtain the extracts, and further clean-up was carried out by applying the streamlined procedure on a multiplug filtration clean-up column coupled with a syringe. The sorbent used for clean-up in this research is multiwalled carbon nanotubes, which was mixed with anhydrous magnesium sulfate to remove water from the extracts. This method was validated on 40 representative pesticides and apple, cabbage, and potato sample matrices spiked at two concentration levels of 10 and 100 μg/kg. It exhibited recoveries between 71 and 117% for most pesticides with RSDs < 15%. Matrix-matched calibrations were performed with the coefficients of determination >0.995 for most studied pesticides between concentration levels of 10–500 μg/L. The LOQs for 40 pesticides ranged from 2 to 50 μg/kg. The developed method was successfully applied to the determination of pesticide residues in market fruit and vegetable samples.

Spinach or Amaranth May Represent Highest Residue of Thiophanate-Methyl with Open Field Application on Six Leaf Vegetables

Co-reporter:Sufang Fan;Pengyue Zhao;Fengzu Zhang

Bulletin of Environmental Contamination and Toxicology 2013 Volume 90( Issue 4) pp:477-481

Publication Date(Web):2013 April

DOI:10.1007/s00128-012-0925-z

To select representative crop among leaf vegetables which may contain the highest residue after fungicide uses, open field applications with thiophanate-methyl on six crops including pakchoi, rape, crown daisy, amaranth, spinach and lettuce were designed and conducted. In this study, a high-performance liquid chromatography and electrospray ionization-tandem mass spectrometry with selected reaction monitoring was used to simultaneously determine thiophanate methyl and its metabolite carbendazim residue in various samples. The limit of quantification for thiophanate methyl and carbendazim were established in the range of 0.005–0.01 mg kg−1 for all samples. It was shown that recoveries ranged from 67.8 % to 102.3 % for thiophanate methyl, and 72.0 %–112.6 % for carbendazim at spiked levels of 0.01–0.1 mg kg−1. It’s found that thiophanate methyl converts to carbendazim very quickly. In supervised field trials, the half-lives of thiophanate methyl in six leaf vegetables were in the range of 1.26–2.65 days, and the half-lives of carbendazim were in the range of 2.53–4.28 days. It was also found that thiophanate methyl residue in spinach and amaranth was higher than others after application. It’s recommended that spinach or amaranth can be selected as representative crop in leaf vegetables in study of systemic fungicides with similarity as thiophanate methyl.

Uniconazole Residue and Decline in Wheat and Soil Under Field Application

Co-reporter:Fengzu Zhang;Sufang Fan;Kejia Gu

Bulletin of Environmental Contamination and Toxicology 2013 Volume 90( Issue 4) pp:499-503

Publication Date(Web):2013 April

DOI:10.1007/s00128-012-0945-8

Uniconazole residue dynamics and final residues in supervised field trials at GAP conditions were studied. The residue levels and dissipation rate of uniconazole was detected by LC–MS. At fortification levels of 0.04, 0.2 and 2 mg kg−1, recoveries ranged from 78.7 % to 100.9 % with RSDs of 0.1 %–4.6 % (n = 5). The dissipation experiments showed the half-lives (T1/2) of uniconazole in soil and wheat plants were 2.9–3.3 and 3.8–4.4 days, respectively. At pre-harvest intervals (PHI) of 45 and 60 days, uniconazole residue were no detectable or below the limit of quantification (LOQ) in soil, wheat plants and wheat.

Dissipation Rate and Residual Fate of Thiamethoxam in Tobacco Leaves and Soil Exposed to Field Treatments

Co-reporter:Xiuguo Wang;Zhenbo Xiang;Xiaoyang Yan

Bulletin of Environmental Contamination and Toxicology 2013 Volume 91( Issue 2) pp:246-250

Publication Date(Web):2013 August

DOI:10.1007/s00128-013-1043-2

A two-year field experiment was conducted in two different locations to investigate the dissipation rate and residual fate of thiamethoxam in tobacco leaves and soil by high performance liquid chromatography with UV detection. The average recoveries for green, cured tobacco leaves and soil ranged from 89.7 %–94.8 %, 90.6 %–94.4 % and 89.0%–92.8 %, respectively, with relative standard deviations between 2.7 % and 9.2 %. The dissipation rates of thiamethoxam were described by first-order kinetics and its half-life values were in the range of 3.9–4.4 days in green tobacco leaves and 12.0–19.1 days in soil, respectively. The residue levels of thiamethoxam at harvest time ranged from 0.020–0.541 mg/kg in cured tobacco leaves, and 0.005–0.019 mg/kg in soil, respectively.

Dissipation and residues of bispyribac-sodium in rice and environment

Co-reporter:Qian Zhang;Yang Zhao;Sufang Fan;Aijuan Bai

Environmental Monitoring and Assessment 2013 Volume 185( Issue 12) pp:9743-9749

Publication Date(Web):2013 December

DOI:10.1007/s10661-013-3287-z

The dissipation and residues of bispyribac-sodium in rice cropping system were studied. Bispyribac-sodium residues were extracted by a simple analytical method based on QuEChERs and detected by LC-MS/MS. The limit of detection for bispyribac-sodium of this method was 0.375 × 10−3 ng. The limit of quantification (LOQ) was 5.0 μg/kg for rice plant samples, 2.0 μg/kg for rice hull, 0.2 μg/kg for water, and 0.1 μg/kg for soil and husked rice samples. The average recoveries of bispyribac-sodium ranged from 74.7 to 108 %, with relative standard deviations less than 13 %. The half-lives of bispyribac-sodium in rice plant, water, and soil were in the range of 1.4–5.6 days. More than 90 % of bispyribac-sodium residue dissipated within 5 days. The final residues of bispyribac-sodium in rice were all below LOQ at harvest time.

Multi-walled carbon nanotubes as alternative reversed-dispersive solid phase extraction materials in pesticide multi-residue analysis with QuEChERS method

Co-reporter:Pengyue Zhao, Lei Wang, Li Zhou, Fengzu Zhang, Shu Kang, Canping Pan

Journal of Chromatography A 2012 Volume 1225() pp:17-25

Publication Date(Web):17 February 2012

DOI:10.1016/j.chroma.2011.12.070

A multi-residue method based on modified QuEChERS sample preparation with multi-walled carbon nanotubes (MWCNTs) as reversed-dispersive solid phase extraction (r-DSPE) material and gas chromatography–mass spectrometry determination by selected ion monitoring (GC/MS-SIM) mode was validated on 30 representative pesticides residues in vegetables and fruits. The acetonitrile-based QuEChERS (quick, easy, cheap, effective, rugged and safe) sample preparation technique was used to obtain the extracts, and the further cleanup was carried out by applying r-DSPE. It was found that the amount of MWCNTs influenced the cleanup performance and the recoveries. The optimal amount of 10 mg MWCNTs was suitable for cleaning up all selected matrices, as a suitable alternative r-DSPE material to primary secondary amine (PSA). This method was validated on cabbage, spinach, grape and orange spiked at concentration levels of 0.02 and 0.2 mg/kg. The recoveries of 30 pesticides were in the range of 71–110%, with relative standard deviations (RSDs, n = 5) lower than 15%. Matrix effects were observed by comparing the slope of matrix-matched standard calibration with that of solvent. Good linearity was achieved at the concentration levels of 0.02–0.5 mg/L. The limits of quantification (LOQs) and the limits of detection (LODs) for 30 pesticides ranged from 0.003 to 0.05 mg/kg and 0.001 to 0.02 mg/kg at the signal-to-noise ratio (S/N) of 10 and 3, respectively. The method was successfully applied to analysis real samples in Beijing. In conclusion, the modified QuEChERS method with MWCNTs cleanup step showed reliable method validation performances and good cleanup effects in this study.Highlights► A method for analysis 30 pesticide residues in vegetables and fruits was developed. ► The original QuEChERS method was employed. ► The extract was cleaned up by r-DSPE using mixture of MWCNTs, instead of PSA. ► Recoveries ranged from 71% to 110% with RSDs lower than 15%. ► The method was successfully applied to the real samples.

Determination of Multiresidues in Rapeseed, Rapeseed Oil, and Rapeseed Meal by Acetonitrile Extraction, Low-Temperature Cleanup, and Detection by Liquid Chromatography with Tandem Mass Spectrometry

Co-reporter:Yaping Jiang, Yanjie Li, Yuting Jiang, Jianguo Li, and Canping Pan

Journal of Agricultural and Food Chemistry 2012 Volume 60(Issue 20) pp:5089-5098

Publication Date(Web):May 2, 2012

DOI:10.1021/jf3004064

A multiresidue method for determining pesticides in rapeseed, rapeseed oil, and rapeseed meal by use of liquid chromatography–tandem mass spectrometry is developed. Samples were extracted with acetonitrile or acidified acetonitrile and cleaned up by a 12 h freezing step. The recovery data were obtained by spiking blank samples at three concentration levels. The recoveries of 27 selected pesticides in rapeseed, rapeseed oil, and rapeseed meal were in the range of 70–118%, at the concentration level of 10 μg kg–1, with intraday and interday precisions of lower than 22 and 27%, respectively. Linearity was studied between 2 and 500 μg L–1 with determination coefficients (R2) of higher than 0.98 for all compounds in the three matrices. The limits of quantitation (LOQs) of pesticides in rapeseed, rapeseed oil, and rapeseed meal ranged from 0.3 to 18 μg kg–1. The n-octanol–water partition coefficient showed more influence than water solubility in extracting pesticides by acetonitrile from matrices of high fat content. This method was successfully applied for routine analysis in commercial products.

Dispersive Cleanup of Acetonitrile Extracts of Tea Samples by Mixed Multiwalled Carbon Nanotubes, Primary Secondary Amine, and Graphitized Carbon Black Sorbents

Co-reporter:Pengyue Zhao, Lei Wang, Yaping Jiang, Fengzu Zhang, and Canping Pan

Journal of Agricultural and Food Chemistry 2012 Volume 60(Issue 16) pp:4026-4033

Publication Date(Web):April 5, 2012

DOI:10.1021/jf205351t

A method for analysis of 37 pesticide residues in tea samples was developed and validated and was based on reversed-dispersive solid-phase extraction (r-DSPE) cleanup in acetonitrile solution, followed by liquid chromatography–electrospray tandem mass spectrometry determination. Green tea, oolong tea, and puer tea were selected as matrixes and represent the majority of tea types. Acetonitrile was used as the extraction solvent, with sodium chloride and magnesium sulfate enhancing partitioning of analytes into the organic phase. The extract was then cleaned up by r-DSPE using a mixture of multiwalled carbon nanotubes, primary secondary amine, and graphitized carbon black as sorbents to absorb interferences. Further optimization of sample preparation and determination allowed recoveries of between 70% and 111% for all 37 pesticides with relative standard deviations lower than 14% at two concentration levels of 10 and 100 μg kg–1. Limits of quantification ranged from 5 to 20 μg kg–1 for all pesticides. The developed method was successfully applied to the determination of pesticide residues in market tea samples.

Ionic liquid-based vortex-assisted dispersive liquidliquid microextraction of organophosphorus pesticides in apple and pear

Co-reporter:Lijin Zhang;Fang Chen;Shaowen Liu;Biyu Chen

Journal of Separation Science 2012 Volume 35( Issue 18) pp:2514-2519

Publication Date(Web):

DOI:10.1002/jssc.201101060

An ionic liquid-based vortex-assisted dispersive liquid–liquid microextraction (DLLME) was developed for the analysis of trace amounts of six organophosphorus pesticides (OPPs) in apple and pear coupled with high-performance liquid chromatography. During the DLLME, the effect of some experimental factors including extraction solvent and its volume, dispersion solvent and its volume, vortex time, salt addition, and pH on the extraction procedure were investigated. Under the chosen extraction conditions, the analytes were enriched more than 300-fold and the limits of detections were greatly dropped to 0.061–0.73 μg/kg. The linearity relationship was observed in the range of 2–100 μg/kg with the correlation coefficients (R²) ranging from 0.9967 to 0.9983. The relative standard deviations varied from 2.3 to 5.7% (n = 6). Mean recovery values of the OPPs were in the range of 69.8–109.1% with a relative standard deviation lower than 7.0%. Based on these above, it could be concluded that 1-octyl-3-methylimidazolium hexafluorophosphate ([C₈MIM][PF₆]) was a good extraction solvent and the proposed [C₈MIM][PF₆]-based vortex-assisted DLLME method was suitable for the effective extraction of the OPPs in apple and pear.

Determination of pesticide residues in complex matrices using multi-walled carbon nanotubes as reversed-dispersive solid-phase extraction sorbent

Co-reporter:Pengyue Zhao;Lei Wang;Jinhui Luo;Jianguo Li

Journal of Separation Science 2012 Volume 35( Issue 1) pp:153-158

Publication Date(Web):

DOI:10.1002/jssc.201100566

Abstract

A modified quick, easy, cheap, effective, rugged and safe (QuEChERS) method with multi-walled carbon nanotubes (MWCNTs) as a reversed-dispersive solid-phase extraction (r-DSPE) material combined with gas chromatography-mass spectrometry was developed for the determination of 14 pesticides in complex matrices. Four vegetables (leek, onion, ginger and garlic) were selected as the complex matrices for validating this new method. This technique involved the acetonitrile-based sample preparation and MWCNTs were used as the r-DSPE material in the cleanup step. Two important parameters influencing the MWCNTs efficiency, the external diameters and the amount of MWCNTs used, were investigated. Under the optimized conditions, recoveries of 78–110% were obtained for the target analytes in the complex matrices at two concentration levels of 0.02 and 0.2 mg/kg. In addition, the RSD values ranged from 1 to 13%. LOQs and LODs for 14 pesticides ranged from 2 to 20 μg/kg and from 1 to 6 μg/kg, respectively.

Preparation of molecularly imprinted polymers: Diethyl(3-methylureido)(phenyl)methylphosphonate as a dummy template for the recognition of its organophosphate pesticide analogs

Co-reporter:Shu Kang;Yun Xu;Li Zhou

Journal of Applied Polymer Science 2012 Volume 124( Issue 5) pp:3737-3743

Publication Date(Web):

DOI:10.1002/app.35373

Abstract

A novel compound, diethyl(3-methylureido)(phenyl)methylphosphonate (DEP), possessing an organophosphate skeleton, was synthesized and used as a dummy template to prepare molecularly imprinted polymers (MIPs) for the recognition of organophosphate pesticide analogs. Computational modeling was used to study the primary intermolecular interactions in the prepolymerization mixture. It was found that the interaction force between DEP and the monomers was hydrogen bonding. A series of MIPs were synthesized with different monomers and were evaluated by adsorption experiments, which showed that methacrylic acid was used as an appropriate monomer and a molar ratio of DEP to MAA of 1 : 9 was optimal. Scatchard analysis showed that there might have been two types of binding sites in the MIPs. DEP and several pesticides were used in molecular recognition specificity tests of DEP–MIP, which exhibited better selectivity and reservation ability for organophosphate pesticides, such as methamidophos and orthene, possessing amino or imino groups and a smaller steric hindrance. On the basis of the use of a dummy molecule as template, the problem of template leakage could be avoided; this, thereby, improved the specificity of analysis. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Dissipation of Diethyl Aminoethyl Hexanoate (DA-6) Residues in Pakchoi, Cotton Crops and Soil

Co-reporter:Yaping Jiang;Yuting Jiang;Shun He

Bulletin of Environmental Contamination and Toxicology 2012 Volume 88( Issue 4) pp:533-537

Publication Date(Web):2012 April

DOI:10.1007/s00128-012-0565-3

QuEChERS procedure and acetonitrile extraction, oscillation and ultrasonic procedure followed by GC–MS and LC–MS/MS (QqQ) detections were established for determination of diethyl aminoethyl hexanoate (DA-6) residues in pakchoi, cotton leaf, cotton seed and soil. At concentration levels of 0.005–1 mg kg−1, recoveries were in the range of 80.5%–103.3%, with a RSD less than 14.2%. The LOQs of methods were 0.005, 0.003, 0.005 and 0.001 mg kg−1 for the pakchoi, cotton leaf, soil and cotton seed samples, respectively. DA-6 was applied in supervised field trials at GAP conditions to pakchoi and cotton. It was found that the dissipation half-lives of DA-6 were 5.4–8.2 days and 1.1–2.2 days and 1.5–1.9 days in cotton crop, pakchoi and soil respectively. At harvest, no detectable residues (

Determination of Six Neonicotinoid Insecticides Residues in Spinach, Cucumber, Apple and Pomelo by QuEChERS Method and LC–MS/MS

Co-reporter:Fengzu Zhang;Yanjie Li;Chuanshan Yu

Bulletin of Environmental Contamination and Toxicology 2012 Volume 88( Issue 6) pp:885-890

Publication Date(Web):2012 June

DOI:10.1007/s00128-012-0579-x

A modified QuEChERS and LC–MS/MS method has been developed for the simultaneous determination of residues of six neonicotinoids in various crops, including spinach, cucumber, apple and pomelo. The method showed good linearity (R2 ≥ 0.9995) and precision (RSD ≤ 14.0%). Average recoveries of the six neonicotinoids ranged between 73.7% and 103.8% at spiking levels 0.005, 0.1 and 1 mg kg−1. The LODs and LOQs were in the ranges of 0.20–0.85 μg kg−1 and 0.66–2.84 μg kg−1, respectively. The method was satisfactorily validated for the analysis of 50 agricultural samples. Imidacloprid and imidaclothiz were detected at concentration levels ranging from 7 to 5.3 μg kg−1.

Dissipation and Residues of Monosultap in Rice Plant and Environment

Co-reporter:Fengzu Zhang;Lei Wang;Li Zhou

Bulletin of Environmental Contamination and Toxicology 2012 Volume 88( Issue 3) pp:362-367

Publication Date(Web):2012 March

DOI:10.1007/s00128-011-0437-2

A modified method for the analysis of monosultap residue in rice plant and environment was developed and validated. Monosultap residue dynamics and final residues in supervised field trials at GAP conditions were studied. At fortification levels of 0.05, 0.5 and 1 mg kg−1, it was shown that recoveries ranged from 75.0% to 109.2% with RSDs of 1.2–5.1% (n = 5). The dissipation experiments showed the half-lives (T1/2) of monosultap in water, soil and rice plants were 1.1–1.9, 1.4–2.1 and 1.3–2.1 days, respectively. At pre-harvest intervals (PHI) of 21 and 30 days, monosultap residue were 0.01–0.06 mg kg−1 in soil, 0.01–0.19 mg kg−1 in rice plants, and 0.01–0.09 mg kg−1 in husked rice.

Development of a Method for the Simultaneous Determination of Six Sulfonylurea Herbicides in Wheat, Rice, and Corn by Liquid Chromatography–Tandem Mass Spectrometry

Co-reporter:Shu Kang, Na Chang, Yang Zhao, and Canping Pan

Journal of Agricultural and Food Chemistry 2011 Volume 59(Issue 18) pp:9776-9781

Publication Date(Web):July 31, 2011

DOI:10.1021/jf2020073

A sensitive and reliable method was developed and validated for trace determination of sulfonylurea herbicides residues in cereals (wheat, rice, and corn) by liquid chromatography–tandem mass spectrometry. The selected analytes were ethoxysulfuron, ethametsulfuron-methyl, bensulfuron-methyl, chlorimuron-ethyl, pyrazosulfuron-ethyl, and cyclosulfamuron. In this work, the extraction procedure was performed by using a mixture solvent of phosphate buffer (pH 9.5)/acetonitrile (8:2, v/v) as the extraction solvent and then was cleaned up by using Spe-ed C18/18% SPE cartridges, providing good recoveries for all of the tested analytes and with no matrix effects affecting method accuracy. The limits of detection for the studied analytes in cereal samples were between 0.043 and 0.23 μg kg–1, and the limits of quantification were between 0.14 and 0.77 μg kg–1, lower in all cases than the maximum residue limits permitted by the European Union for this kind of food. The developed methodology has demonstrated its suitability for the monitoring of these residues in cereal samples with high sensitivity, precision, and satisfactory recoveries.

Residue Dynamic of Pyrimorph on Tomatoes, Cucumbers and Soil under Greenhouse Trails

Co-reporter:Jing Wang;Lianlian Zhao;Xuesheng Li

Bulletin of Environmental Contamination and Toxicology 2011 Volume 86( Issue 3) pp:326-330

Publication Date(Web):2011 March

DOI:10.1007/s00128-011-0201-7

A modified QuEChERS method for analysis of pyrimorph residue in tomatoes, cucumbers and soil was developed and validated. Residue dynamics and final residues in greenhouse vegetables and soil were studied. At fortification levels of 0.05, 0.1 and 1 mg kg−1 in tomatoes, cucumbers and soil, the method got recoveries ranged from 86.1% to 99.3% with relative standard deviations of 1.0%–7.7%, in agreement with directives for method validation in residue analysis. The limit of determination in tomatoes, cucumbers and soil was 0.05 mg kg−1. The proposed method was successfully employed for the determination of pyrimorph residue levels and dissipation rates in vegetables and soil. At six experimental sites, pyrimorph residues in tomatoes and cucumbers showed relatively fast dissipation rates, with half-lives of 5.8–7.7 days and 5.7–7.1 days respectively. Half-lives of pyrimorph in soil were 8.5–11.0 days. The final residues of pyrimorph in tomatoes ranged from 0.19 to 3.66 mg kg−1, 0.18 to 4.35 mg kg−1 in cucumbers and 0.22 to 16.5 mg kg−1 in soil with pre-harvest interval of 3–7 days. 5 mg kg−1 was proposed as the MRL of pyrimorph in tomatoes and cucumbers.

Residue Dynamics of Clopyralid and Picloram in Rape Plant Rapeseed and Field Soil

Co-reporter:Pengyue Zhao;Lei Wang;Li Chen

Bulletin of Environmental Contamination and Toxicology 2011 Volume 86( Issue 1) pp:78-82

Publication Date(Web):2011 January

DOI:10.1007/s00128-010-0184-9

A new method for simultaneous analysis of clopyralid and picloram residues in rape plant, rapeseed and field soil was developed and validated. The residual dynamics and final residues of clopyralid and picloram in rape plant, rapeseed and soil were determined by High Performance Liquid Chromtography-Diode Array Detector (HPLC-DAD) and High Performance Liquid Chromtography-Mass Spectroscopy Detector (HPLC-MSD). The limit of quantification (LOQ) was established as 0.02 mg/kg for soil sample, 0.5 mg/kg for rape and rapeseed sample, respectively. It was shown that recoveries ranged from 71.3%–109.0% for clopyralid, and 84.0%–100.5% for picloram at fortified levels of 0.02–2 mg/kg. From residue trials at two geographical experimental plots in China and laboratory simulated pots, the results showed that the half-lives of clopyralid in rape and soil were 3.66–4.83 and 2.53–5.17 days, respectively, for picloram with half-lives of 5.17–10.73 and 3.45–7.11 days. For tirals applied according to the label recommended, at harvest time the final residues of clopyralid in rapeseed were below 1.82 mg/kg, while the picloram residues could not be detected in rapeseed (

Dissipation and Residues of Fluroxypyr-meptyl in Rice and Environment

Co-reporter:Lei Wang;Jun Xu;Pengyue Zhao

Bulletin of Environmental Contamination and Toxicology 2011 Volume 86( Issue 4) pp:449-453

Publication Date(Web):2011 April

DOI:10.1007/s00128-011-0218-y

A simple and reliable analytical method for analysis of fluroxypyr-meptyl residue in rice, soil and water was investigated. The residue levels and dissipation rates of fluroxypyr-meptyl (34% AS) were determined by GC–MSD in selected ion monitoring mode. In the supervised field trials, the half-life of fluroxypyr- meptyl in rice plant was in the range 1.25–4.13 days. The half-lives of fluroxypyr-meptyl in soil and water were 2.29 and 1.73 days, respectively. In order to assess the dissipation of fluroxypyr-meptyl in the environment, a laboratory simulated experiment was carried out in soil and water. The terminal residues of fluroxypyr-meptyl in rice plant, husked rice, rice hull and soil samples were undetectable at harvest. It showed that fluroxypyr-meptyl may be safe to use according to the recommended dosage suggested by the corporation.

Dissipation and Residues Detection of Dioctyldiethylenetriamine Cetate in Rice Plant and Environment by QuEChERS Method and Liquid Chromatography/Electrospray Tandem Mass Spectrometry

Co-reporter:Xuesheng Li;Yaping Jiang;Weili Shan

Bulletin of Environmental Contamination and Toxicology 2010 Volume 84( Issue 5) pp:596-601

Publication Date(Web):2010 May

DOI:10.1007/s00128-010-0001-5

Dioctyldiethylenetriamine acetate (Chinese common name: Xinjunan) is an effective bactericide and virucide widely used on many crops including vegetables and fruits in China. In this study, the dissipation of dioctyldiethylenetriamine acetate 1.8% (w/w) aqueous solution (AS) in rice, soil and water was studied. The result in the supervised field trials showed that the half-lives of dioctyldiethylenetriamine acetate in soil and rice plant were in the range 3.9–6.6 and 6.2–12 days, respectively. It also indicated that the decline followed first-order kinetics. The dissipation of Xinjunan in water, was stimulated in a laboratory container, showed that it could rapidly deposit on solid particles and might form bound residues in surface levels of soil. According to the toxicological data and the dietary intake of rice, a MRL (Maximum Residue Limits) of 0.1 mg/kg for dioctyldiethylenetriamine acetate in the rice was recommended for national accessment. The results indicated that the supervised trials median residues (STMR) is 0.02 mg/kg and only 0.2% of the acceptable daily intake (ADI) is occupied by dietary daily intake in the average Chinese population. It would be unlikely to pose any public health issues if dioctyldiethylenetriamine acetate was applied according to the use pattern suggested by the manufactures on the label.

The application of monolithic columns in pesticides analysis

Co-reporter:Jinfang Wang;Yanjun Xu;Shuren Jiang;Shuaigang Liu

Journal of Separation Science 2007 Volume 30(Issue 1) pp:3-7

Publication Date(Web):15 DEC 2006

DOI:10.1002/jssc.200600232

HPLC and HPLC/MS are the most widely used analytical techniques in the field of pesticides analysis. In recent years, there has been considerable focus on fast separations in HPLC in order to reduce analysis time as well as cost. Monolithic columns, consisting of continuous beds with macropores and mesopores, can meet this requirement and have been widely used in the medical and biological fields. However, it has seldom been used when analyzing pesticides. In this work, the application of monolithic columns in pesticides analysis and their advantages are evaluated and compared with those obtained using conventional packed columns.

The effects of oxygenation aeration treatment on dissipation behaviors of tricaine mesylate in carp (Cyprinus carpio) muscle and water

Co-reporter:Yuhong Qin, Jingru Zhang, Yuang Zhang, Fangbing Li, Yanjie Li, Yongtao Han, Nan Zou, Canping Pan

Food Control (July 2017) Volume 77() pp:50-56

Publication Date(Web):1 July 2017

DOI:10.1016/j.foodcont.2017.01.027

•A rapid analysis method of MS-222 was developed in carp muscle and water samples.•The dissipation behavior of MS-222 under oxygen supply treatment was investigated.•Oxygenation aeration treatment contributed to the dissipation of MS-222.•Three days of withdrawal period was recommended in carps after MS-222 used.Tricaine mesylate (MS-222) is one of the most used anesthetics in fish. It can be absorbed by the human body via food consumption, with related detriments to human health. In this study, a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) method was developed for the determination of MS-222 in carp muscle and water samples using liquid chromatography-tandem mass spectrometry (LC-MS/MS). For cleanup procedure, multiplug filtration cleanup (m-PFC) method with n-Hexane delipidation was adopted. The extraction solvent, cleanup methods and sorbents were optimized. All method validation parameters were in the acceptable range. The dissipation behavior study was followed by the method development. Firstly, the anesthesia dose and time were optimized in application study. Secondly, carps were revived for different period of time with (experimental group) and without (control group) the oxygenation aeration treatment to compare the dissipation rate of MS-222. After being anesthetized for 6 h at 50 mg/L and 12 h of elimination, the concentrations of MS-222 in crap muscle and water of experimental group was lower than those of control group. After 36 h of elimination under oxygenation aeration, over 90% of MS-222 was dissipated in carp muscle. The results showed that the half-life of MS-222 in carp muscle was 6.2 h. The findings suggested that the commonly-used oxygenation aeration treatment in aquaculture production had potential effects in accelerating the dissipation of MS-222 in carp and water. In this study, three days of withdrawal period was recommended in carps after MS-222 administration under oxygenation aeration.