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Xu Y.,Institute for the Control of Agro chemicals of Zhejiang Province | Shou L.-F.,Institute for the Control of Agro chemicals of Zhejiang Province | Wu Y.-L.,The Ningbo Academy of Agricultural science
Journal of Chromatography A | Year: 2011

This paper presents a rapid analytical method for the simultaneous determination of flonicamid and its metabolites N-(4-trifluoromethylnicotinoyl) glycine (TFNG), 4-trifluoromethylnicotinic acid (TFNA), and 4-trifluoromethylnicotinamide (TFNA-AM) in vegetables using QuEChERS by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Samples were extracted with acetonitrile. The extract was purified through QuEChERS method with primary secondary amine (PSA) and graphite carbon black (GCB). Then the extract was diluted with 0.1% formic acid in water, and analyzed by LC-MS/MS on a Waters Acquity BEH C18 column with methanol/0.1% formic acid in water as mobile phase with gradient elution. The linearity of the analytical response across the studied range of concentrations (0.20-500μg/L) was excellent, obtaining correlation coefficients higher than 0.998. No significant matrix effects were observed. Recovery studies were carried out on spiked spinach and cucumber blank samples, at four concentration levels (0.01, 0.05, 0.50 and 2.0mg/kg) performing six replicates at each level. Mean recoveries of 81.3-94.8% with CVs of 2.4-7.0% were obtained. The method demonstrated to be suitable for the simultaneous determination of flonicamid and its metabolites in vegetables. © 2011 Elsevier B.V. Source


Li C.,Tianjin Agricultural University | Yang T.,The Ningbo Academy of Agricultural science | Wu Y.-L.,The Ningbo Academy of Agricultural science
Ecotoxicology and Environmental Safety | Year: 2012

The degradation behavior of metaflumizone was studied in a rice field ecosystem, and a simple and reliable analytical method was developed for determination of metaflumizone in soil, rice straw, paddy water and brown rice. Metaflumizone residues were extracted from samples with acetonitrile. The extract was cleaned up with QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method, and determined by liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). The average recoveries of metaflumizone were 75.2-105.1 percent from soil, rice straw, paddy water and brown rice. The relative standard deviations were less than 15 percent. The limits of quantitation (LOQs) of metaflumizone were 3.0μg/L for paddy water and 3.0μg/kg for other samples. The results of the kinetic study of metaflumizone residue showed that metaflumizone degradation in soil, water and rice straw coincided with C=0.08564e-0.0505t, C=0.04984e-0.1982t, C=2.2572e-0.1533t, respectively; the half-lives were about 13.7d, 3.5d, and 4.5d, respectively. The final residues of metaflumizone on brown rice were lower than maximum residue limit (MRL) of 0.05mg/kg after 28d Pre-Harvest Interval (PHI) at the recommended dosage. Therefore, a dosage of 450mLa.i.ha-1 with 28 days before harvest was recommended, which could be considered as safe to human beings and animals. © 2012 Elsevier Inc. Source


Zhang J.-M.,Zhejiang Academy of Agricultural Sciences | Chai W.-G.,The Ningbo Academy of Agricultural science | Wu Y.-L.,The Ningbo Academy of Agricultural science
Chemosphere | Year: 2012

The fate of chlorantraniliprole was studied in rice field ecosystem, and a simple and reliable analytical method was developed for determination of chlorantraniliprole in soil, rice straw, paddy water and brown rice. Chlorantraniliprole residues were extracted from samples with acetonitrile. The extract was cleaned up with QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method, and determined by high-performance liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). The average recoveries were 76.9-82.4% from soil, 83.6-89.3% from rice straw, 95.2-103.1% from paddy water and 84.9-87.7% from brown rice. The relative standard deviation was less than 15%. The limits of detection (LODs) of chlorantraniliprole calculated as a sample concentration (S/N ratio of 3) were 0.012μgL -1 for paddy water, 0.15μgkg -1 for soil, brown rice and rice straw. The results of the kinetics study of chlorantraniliprole residue showed that chlorantraniliprole degradation in soil, water and rice straw coincided with C=0.01939e -0.0434t, C=0.01425e -0.8111t, and C=1.171e -0.198t, respectively; the half-lives were about 16.0 d, 0.85 d and 3.50d, respectively. The degradation rate of chlorantraniliprole in water was the fastest, followed by rice straw. The final residues of chlorantraniliprole on brown rice were lower than maximum residue limit (MRL) of 0.02mgkg -1 after 14d Pre-Harvest Interval (PHI). Therefore, a dosage of 150mL a.i.hm -2 was recommended, which could be considered as safe to human beings and animals. © 2011 Elsevier Ltd. Source


Zhao L.,Shanghai Agriculture Technical Extension Service Center | Chen G.,The Ningbo Academy of Agricultural science | Zhao J.,The Ningbo Academy of Agricultural science | Zhang Y.,The Ningbo Academy of Agricultural science | And 3 more authors.
Chemosphere | Year: 2015

The fate of spinetoram was studied in a rice field ecosystem, and an efficient method for the determination of spinetoram (XDE-175-J and XDE-175-L) in soil, rice straw, paddy water, husk and brown rice was developed. Spinetoram residues were extracted from samples with a salting out extraction procedure. The extracts were diluted with 0.10% formic acid in water and analysed with liquid chromatography tandem mass spectrometry (LC-MS/MS) on a Waters Acquity BEH C18 column. The calibration curve was linear in the range 0.125-100μgL-1 and r>0.999. The average recovery was 82.9-89.0% from soil, 78.5-92.1% from rice straw, 93.6-100.3% from paddy water, 79.1-87.9% from brown rice and 72.7-82.9% from husk. The relative standard deviation (RSD) was less than 10%. These results are all within the accepted range for pesticide residue determination. The field test results showed that spinetoram degradation in paddy water, soil and rice straw coincided with C=0.0132e-1.9685t, C=0.0308e-0.1018t and C=0.8530e-0.6223t, respectively. The half-lives of spinetoram in paddy water, soil and rice straw were 0.35, 6.8 and 1.1d, respectively. The final residue level was lower than the maximum residue limit (MRL) of 0.05mgkg-1 for spinetoram in rice with a harvest interval of 7d. A dosage of 450mLha-1 was recommended, which can be considered safe for human beings and animals. The results of this study will contribute to establishing the scientific basis of the dosage of spinetoram for agricultural fields. © 2014 Elsevier Ltd. Source

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