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Chen C.,Chinese Academy of Agricultural Sciences | Qian Y.,Chinese Academy of Agricultural Sciences | Tao C.,Chinese Institute for the Control of Agrochemicals | Li Y.,Chinese Academy of Agricultural Sciences
Food Control | Year: 2011

In the present study an effort has been made to evaluate the residues of selected insecticides (organophosphorous and pyrethroid) and fungicides (triazoles and chloronitriles) in fruits and vegetables collected from Xiamen, China, during the October 2006 to March 2009 monitoring campaign. Gas chromatography with electron capture detector (GC-ECD) was used to determine the concentrations of 22 pesticide residues among those recommended for pest treatment. Of 1135 samples (37.7%) that contained pesticide residues, pakchoi cabbage, legumes, and leaf mustard were the commodities in which pesticide residues were most frequently detected, with 17.2%, 18.9% and 17.2% of the samples exceeding the maximum residue limits (MRLs), respectively. Concerning the most frequently detected pesticide residues, cypermethrin was found in 18.7% of the samples analyzed. Data obtained were then used for estimating the potential health risks associated with the exposures to these pesticides. The estimated daily intakes (EDIs) range from 0.1% of the ADI for cyfluthrin to 2.61% of the ADI for omethoate and 0.1% of the ADI for omethoate. The most critical commodity is legumes, contributing 2.61% to the hazard index (HI). The results show that despite a high occurrence of pesticide residues in fruits and vegetables from this region, it could not be considered a serious public health problem. Nevertheless, an investigation into continuous monitoring and tighter regulation of pesticide residues in fruits and vegetables is recommended. © 2011 Elsevier Ltd.


Gui W.,Zhejiang University | Xu Y.,Chinese Institute for the Control of Agrochemicals | Shou L.,Chinese Institute for the Control of Agrochemicals | Zhu G.,Zhejiang University | Ren Y.,Centers for Disease Control and Prevention
Food Chemistry | Year: 2010

A high performance liquid chromatography (HPLC) coupled to electrospray ionisation tandem mass spectrometry (MS/MS) method was described for the residue detection of chrysoidine in yellow-fin tuna in the present study. Samples were cleaned up with solid phase extraction (SPE) cartridge, and then injected into HPLC for separation. Multiple-reaction monitoring (MRM) was applied for quantitative determination. Results showed that the low limit of detection (LOD) of the method was 1.25 × 10-12 g, and the low limit of quantification (LOQ) was 0.42 μg/L. The standard calibration curve was y = 2333.9x -845 (r2 > 0.99) with the linear range of 0.63-100 μg/L. The average recoveries of chrysoidine ranged from 86.0% to 108.0% when the spiked concentration was from 0.5 μg/kg to 20 μg/kg. And the developed method also showed the good test precisions (RSD%: 4.38-14.27%). © 2010 Elsevier Ltd. All rights reserved.


Dong F.,Chinese Academy of Agricultural Sciences | Chen X.,Chinese Academy of Agricultural Sciences | Liu X.,Chinese Academy of Agricultural Sciences | Xu J.,Chinese Academy of Agricultural Sciences | And 3 more authors.
Journal of Chromatography A | Year: 2012

The sensitive analytical method using quick, easy, cheap, effective, rugged, and safe (QuEChERS) procedure for simultaneous determination of five novel pyrazole fungicides residues in cereals (rice and wheat), vegetables (cucumber, tomato, and lettuce), and fruits (apple and grape) was developed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The five pyrazole fungicides (bixafen, fluxapyroxad, furametpyr, pyraclostrobin, and rabenzazole) were extracted from seven matrices using acetonitrile and subsequently cleaned up by octadecylsilane (C18) or graphitized carbon black (GCB) prior to LC-MS/MS analysis. The determination of the target compounds was achieved in less than 3.0min using an electrospray ionization source in positive mode (ESI+) for furametpyr, pyraclostrobin, and rabenzazole, while negative mode (ESI-) for bixafen and fluxapyroxad. The method showed excellent linearity (at least R2≥0.990) for all studied analytes. The limits of detection were below 3.0μgkg-1, and the limits of quantification did not exceed 9μgkg-1 in all matrices. The overall average recoveries in rice, wheat, cucumber, tomato, lettuce, apple, and grape at three levels (10, 100 and 1000μgkg-1) were ranged from 70.0% to 108% with all RSDs values less than 20.9% for all analytes. The method is demonstrated to be convenient and reliable for the routine monitoring of pyrazole fungicides in cereals, vegetables and fruits. © 2012 Elsevier B.V.


Lei P.,CAS Beijing National Laboratory for Molecular | Wang F.,CAS Beijing National Laboratory for Molecular | Gao X.,CAS Beijing National Laboratory for Molecular | Ding Y.,CAS Beijing National Laboratory for Molecular | And 4 more authors.
Journal of Hazardous Materials | Year: 2012

Nano titanium dioxide (TiO 2) photocatalyst is generally immobilized onto the matrix through the physical absorption, hydrogen bonding or chemical bonding, which is utilized for the application of wastewater treatment. In this research, TiO 2 nanoparticles were immobilized in polyvinyl alcohol (PVA) matrix via solution-casting combined with heat-treatment method. Structure characterization indicated that TiOC chemical bond formed via dehydration reaction between TiO 2 and PVA during the heat treatment process, and TiO 2 nanoparticles had been chemically immobilized in PVA matrix. Photodegradation results of methyl orange (MO) showed that the film with 10wt% TiO 2 and treated at 140°C for 2h exhibited a remarkable ultraviolet (UV) photocatalytic activity, approximately close to the TiO 2 slurry system. This was mainly attributed to the fixation effect by TiOC chemical bonds, which was indirectly confirmed by the slight loss of TiO 2 photocatalysts even after 25-cycle use. In addition, the good swelling ability of PVA matrix provided the MO molecules with more opportunities to fully contact with TiO 2, thus benefited the photocatalysis. This route to chemically immobilize TiO 2 nanoparticles is simple and cheap to prepare polymer/TiO 2 hybrid materials with high photocatalytic activity for multi-cycle use, which is of significance to the practical application of TiO 2 catalysts. © 2012 Elsevier B.V..


Zhu Y.,Chinese Academy of Agricultural Sciences | Liu X.,Chinese Academy of Agricultural Sciences | Xu J.,Chinese Academy of Agricultural Sciences | Dong F.,Chinese Academy of Agricultural Sciences | And 4 more authors.
Journal of Chromatography A | Year: 2013

A modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) method for the simultaneous determination of spirotetramat and its four metabolites in fruits (apple, peach) and vegetables (cabbage, tomato, potato, cucumber), based on the use of liquid extraction/partition and dispersive solid phase extraction (dispersive-SPE) followed by ultrahigh-performance chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS), was established. Acidified acetonitrile (containing 1% (v/v) acetic acid) as the extraction solvent and simultaneous liquid-liquid partitioning formed by adding anhydrous magnesium sulfate (MgSO4) and anhydrous sodium acetate (NaOAc). The extract was then cleaned up by dispersive-SPE using graphitized carbon black (GCB) as selective sorbent. Further optimization of sample preparation and determination achieved recoveries of between 82 and 110% for all analytes with RSD values lower than 14% in apple, peach, cabbage, tomato, potato and cucumber at three levels (10, 100 and 1000μg/kg). The method showed excellent linearity (R2≥0.9895) for all studied analytes. The determination of the target compounds was achieved in less than 6.0min using an electrospray ionization source in positive mode (ESI+). The method is demonstrated to be convenient and reliable for the routine monitoring of spirotetramat and its metabolites in fruits and vegetables. © 2013 Elsevier B.V.


Chen C.,Chinese Academy of Agricultural Sciences | Qian Y.,Chinese Academy of Agricultural Sciences | Liu X.,Jiangsu Academy of Agricultural Sciences | Tao C.,Chinese Institute for the Control of Agrochemicals | And 2 more authors.
Regulatory Toxicology and Pharmacology | Year: 2012

Chlorpyrifos is a widely used organophosphorus insecticide in agricultural pest control. To understand the residue behavior of chlorpyrifos and to evaluate the dietary risk of chlorpyrifos residue in food in China, a number of residue studies were conducted on rice and cabbage. The supervised trial median residues (STMRs) for rice and cabbage were less than 0.010 and 0.227mgkg -1, respectively. Only 7.4% and 13.3% of acceptable daily intake (ADI) (0-0.01mgkg -1bw) of chlorpyrifos is occupied by dietary daily intake to the Chinese adult and children, respectively, due to the consumption of rice and cabbage. These results on risk assessment were consistent with that of JMPR. Incorporation of market survey residue data gave a 5-fold reduction in the estimated exposures to chlorpyrifos. Concerning the acute exposure, the national estimated short-term intake (NESTI) represents 0.077% and 10.6% for rice and cabbage, respectively, of the acute reference dose (ARfD) (0-0.1mgkg -1bw). The application of chlorpyrifos at the recommended dose on rice and cabbage is unlikely to pose any public health issues if it is applied according to the good agricultural practices (GAPs) established by each country. © 2011 Elsevier Inc.


Guo Y.,Zhejiang University | Tian J.,Zhejiang University | Liang C.,Chinese Institute for the Control of Agrochemicals | Zhu G.,Zhejiang University | Gui W.,Zhejiang University
Microchimica Acta | Year: 2013

We report on a multiplex bead-based competitive immunoassay using suspension array technology for the simultaneous detection of the pesticides triazophos, carbofuran and chlorpyrifos. Three hapten-protein conjugates were covalently bound to carboxylated fluorescent microspheres to serve as probes. The amount of conjugates and antibodies were optimized. The new multi-analyte assay has dynamic ranges of 0.02-50 ng mL-1, 0.5-500 ng mL-1 and 1.0-1000 ng mL-1 for triazophos, carbofuran and chlorpyrifos, respectively, and the detection limits are 0.024, 0.93 and 1.68 ng mL-1. This new multiplex assay is superior to the traditional ELISA in possessing a wider detection range, better reproducibility and the feature of multi-target detection. Cross-reactivity studies indicated that the bead-array method is highly selective for the three target pesticides, and that individual analyses have no significant influence between each other, also without cross-reactions from other structurally related pesticides. The method was applied to analyze vegetables spiked with the three pesticides, and the recoveries were in ranges of 78.5-112.1 %, 72.2-120.2 % and 70.2-112.8 %, respectively, with mean coefficients of variation of <15 %. © 2013 Springer-Verlag Wien.


Liu X.,Chinese Academy of Agricultural Sciences | Xu J.,Chinese Academy of Agricultural Sciences | Dong F.,Chinese Academy of Agricultural Sciences | Li Y.,Chinese Academy of Agricultural Sciences | And 2 more authors.
Analytical and Bioanalytical Chemistry | Year: 2011

The new analytical method using Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) procedure for simultaneous determination of diacylhydrazine insecticide residues in fruits and vegetables was developed using ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). The four insecticides (tebufenozide, methoxfenozide, chromafenozide, and halofenozide) were extracted from six fruit and vegetable matrices using acetonitrile and subsequently cleaned up using primary secondary amine (PSA) or octadecylsilane (C18) as sorbent prior to UPLC-MS/MS analysis. The determination of the target compounds was achieved in less than 3.0 min using an electrospray ionization source in positive mode (ESI+) for tebufenozide, methoxfenozide, and halofenozide and in negative mode (ESI-) for chromafenozide. The limits of detection were below 0.6 μg kg -1, while the limit of quantification did not exceed 2 μg kg -1 in different matrices. The QuEChERS procedure by using two sorbents (PSA and C18) and the matrix-matched standards gave satisfactory recoveries and relative standard deviation (RSD) values in different matrices at four spiked levels (0.01, 0.05, 0.1, and 1 mg kg -1). The overall average recoveries for this method in apple, grape, cucumber, tomato, cabbage, and spinach at four levels ranged from 74.2% to 112.5% with RSDs in the range of 1.4-13.8% (n∈=∈5) for all analytes. This study provides a theoretical basis for China to draw up maximum residue limits and analytical method for diacylhydrazine insecticide in vegetables and fruits. © 2011 Springer-Verlag.


Deng Z.,University of Science and Technology Beijing | Hu J.,University of Science and Technology Beijing | Qin D.,Chinese Institute for the Control of Agrochemicals | Li H.,Chinese Institute for the Control of Agrochemicals
Chromatographia | Year: 2010

A facile and sensitive method utilizing capillary gas chromatography with nitrogen phosphorus detection (GC-NPD) has been developed and validated for simultaneous analysis of hexaconazole, myclobutanil, and tebuconazole, three broad-spectrum systemic fungicides, in apples and soil. Two samples were fortified with the three pesticides and subjected to ultrasonic extraction, followed by solid-phase extraction (SPE) to remove coextractives, before analysis by GC-NPD. SPE procedures were performed on PSA cartridges (500 mg, 3 mL), the analytes being eluted with n-hexane-acetone (9:1 v/v, 2 mL). Recovery of three pesticides from the fortified apple and soil samples ranged from 94.5 to 107.3% with relative standard deviations less than 9.7% at the three spike levels (0.01, 0.1, and 0.5 mg kg-1). Limits of quantification of the method for apple and soil were 0.01 mg kg-1, sufficiently below the maximum residue limits. Direct confirmation of the analytes in samples was achieved by gas chromatography-mass spectrometry (GC-MS). © 2010 Vieweg+Teubner Verlag | Springer Fachmedien Wiesbaden GmbH.


Li J.,Chinese Academy of Agricultural Sciences | Dong F.,Chinese Academy of Agricultural Sciences | Xu J.,Chinese Academy of Agricultural Sciences | Liu X.,Chinese Academy of Agricultural Sciences | And 3 more authors.
Analytica Chimica Acta | Year: 2011

A rapid and effective method for enantioselective determination of simeconazole enantiomers in food products (cucumber, tomato, apple, pear, wheat and rice) has been developed. The enantiomers were resolved by capillary gas chromatography (GC) using a commercial chiral column (BGB-172) and a temperature program from 150°C (held for 1min) and then raised at 10°Cmin -1 to 240°C (held for 10min). This enantioselective gas chromatographic separation was combined with a clean-up/enrichment procedure based on the modification of QuEChERS (quick, easy, cheap, effective, rugged and safe) method. Co-extractives were removed with graphitized carbon black/primary secondary amine (GCB/PSA) solid-phase extraction (SPE) cartridges using acetonitrile:toluene (3:1, v/v) as eluent. Gas chromatography/ion trap mass spectrometry (GC-ITMS) with electron ionization (EI) was then used for qualitative and quantitative determination of the simeconazole enantiomers. Two precursor-to-product ion transitions (m/z 121-101 and 195-153) with the best signal intensity were chosen to build the multiple-reaction monitoring (MRM) acquisition method. The limits of detection for each enantiomer of simeconazole in six food products ranged between 0.4 and 0.9μgkg -1, which were much lower than maximum residue levels (MRLs) established by Japan. The methodology was successfully applied for the enantioselective analysis of simeconazole enantiomers in real samples, indicating its efficacy in investigating the environmental stereochemistry of simeconazole in food matrix. © 2011 Elsevier B.V.

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