Changpeng Zhang

Zhejiang Academy of Agricultural Sciences, Zhegang, Jiangxi Sheng, China

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Publications (6)14.96 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The effects of different steps in canned tomato paste production on difenoconazole levels were investigated. And residues were determined by using ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) after each stage including washing, peeling, homogenization, simmering and sterilization. Results showed that washing and peeling process reduced the amount of residue by 99%, whereas homogenization, simmering, and sterilization process had little effects on the removal of difenoconazole residue. Difenoconazole mostly remained in tomato skin, therefore, washing and peeling significantly reduced difenoconazole, especially peeling resulted in nearly 94.6% difenoconazole removal from tomatoes, with the processing factor of peeling at < 0.05.
    Food Control 02/2012; 23(2):542–546. · 2.82 Impact Factor
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    ABSTRACT: Large amounts of imazethapyr were applied for weed control in cultivation fields in China, but their effects on the soil microbial community remains unclear. In this study, two agricultural soils, a silty loam (HS) and a loamy soil (QL), were spiked with imazethapyr (CK, 0.1, 1 and 10 mg kg(-1)) and incubated for 1, 15, 30, 60, 90 and 120 d. In addition, untreated controls received only water. The soil microbial community structures were characterized by investigating the phospholipid fatty acids (PLFA) and microbial biomass C. Soil microbial biomass C and total concentration of PLFA were variable with incubation time, which were also reduced by the addition of imazethapyr. Imazethapyr addition also decreased the ratios of GN/GP and fungi/bacteria. A larger stress level, measured as the ratio of PLFA (cyc17:0+cyc19:0)/(16:1ω7c+18:1ω7c), was found in the high concentration (1 and 10 mg kg(-1)) herbicide treatment groups. The effects of imazethapyr at the field application on soil microbial biomass and microbial community were minor. Principal component analysis (PCA) of the PLFA clearly separated the treatments and incubation times. Both soils showed different total PLFA concentrations and ratios of GN/GP and fungi/bacteria, but similar changes in the PLFA pattern upon soil treatment. The soil microbial community structure was shifted by the addition of imazethapyr, which recovered after 60d. In addition, the dissipation of imazethapyr was slow in both soils. Our results demonstrated that the addition of imazethapyr shifted the microbial community structure, but that it recovered after a period of incubation.
    Chemosphere 10/2010; 81(6):800-6. · 3.14 Impact Factor
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    ABSTRACT: A sensitive and effective method for the simultaneous quantitative determination of pyrethrin residues in teas was developed and validated using ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). The six major constituents of the pyrethrins (pyrethrin I and II, jasmolin I and II, and cinerin I and II) were successfully separated and independently confirmed in a single run within approximately 5 min. The multi-residue analysis of pyrethrins in teas involved simply extraction with acetonitrile, clean-up using a multilayer solid phase extraction cartridge, and subsequent separation by a hydrophilic end-capped Aquasil C18 columns with detection by tandem mass spectrometry using an electrospray ionization source in positive mode (ESI+). Recovery studies were carried out at three spiked levels (0.05, 0.1, 0.5 mg kg(-1)). The overall average recoveries using this method in green teas and black teas at the three concentration levels ranged from 76.15% to 101.86% with relative standard deviations (RSDs) in the range of 2.71-12.93% (n=5) for all analytes. The limits of detections (LODs) were below 0.009 mg kg(-1), which were lower than the maximum residue limits (MRLs) of 0.5 mg kg(-1) in tea samples established by the European Union legislations in 2008, while the limits of quantification (LOQ) did not exceed 0.03 mg kg(-1). This study provides a theoretical basis for China to draw up MRLs for pyrethrins in teas.
    Analytica chimica acta 09/2010; 678(1):56-62. · 4.31 Impact Factor
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    ABSTRACT: Large quantities of herbicides are used on agricultural soils, but the effects of herbicides on the structure of the soil microbial community have not been well investigated. In this study, soil from three soybean fields was investigated. The herbicide imazethapyr was applied in one year to soil 1 and in two sequential years to soil 2. Control soil received no imazethapyr. Microbial biomass and community structure were characterised using chloroform fumigation–extraction and phospholipid fatty acid (PLFA) determination. The imazethapyr residue was 1.62 μ g·kg in soil 1 and 1.79 μ g·kg in soil 2. The microbial biomass carbon and total PLFAs for soil 2 were much higher than for the other soils. PLFA profiles showed that fatty acids for Gram-negative and Gram-positive bacteria, as well as total bacteria and total fungi in soil 2 were higher than in other samples. Principal component analysis of the PLFAs showed that the structure of the microbial community differed substantially among the three different soybean field soils. Application of the herbicide imazethapyr to soybean fields clearly changed the soil microbial biomass and shifted the structure of the microbial community.
    Chemistry and Ecology 06/2010; 26(3):173-182. · 1.18 Impact Factor
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    ABSTRACT: 2,4-Dichlorophenoxyacetic acid butyl ester (2,4-D butyl ester) is extensively applied for weed control in cultivation fields in China, but its effect on soil microbial community remains obscure. This study investigated the microbial response to 2,4-D butyl ester application at different concentrations (CK, 10, 100 and 1000 μg g−1) in the soils with two fertility levels, using soil dilution plate method and phospholipid fatty acid (PLFA) analysis. Culturable microorganisms were affected by the herbicide in both soils, particularly at the higher concentration. After treating soil with 100 μg g−1 herbicide, culturable bacteria and actinomycetes were significantly higher, compared to other treatments. Treatment of soil with 1000 μg g−1 2,4-D butyl ester caused a decline in culturable microbial counts, with the exception of fungal numbers, which increased over the incubation time. PLFA profiles showed that fatty acids for Gram-negative (GN) bacteria, Gram-positive (GP) bacteria, total bacteria and total fungi, as well as total PLFAs, varied with herbicide concentration for both soil samples. As herbicide concentration increased, the GN/GP ratio decreased dramatically in the two soils. The higher stress level was in the treatments with high concentrations of herbicide (1000 μg g−1) for both soils. Principal component analysis of PLFAs showed that the addition of 2,4-D butyl ester significantly shifted the microbial community structure in the two soils. These results showed that the herbicide 2,4-D butyl ester might have substantial effects on microbial population and microbial community structure in agricultural soils. In particular, the effects of 2,4-D butyl ester were greater in soil with low organic matter and fertility level than in soil with high organic matter and fertility level.
    European Journal of Soil Biology 03/2010; · 2.15 Impact Factor
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    ABSTRACT: A rapid method was developed for the determination of pentachloronitrobenzene (PCNB) and its metabolites pentachloroaniline, pentachlorothioanisole residues in ginseng. Extraction and clean-up were carried out in a single step and analysis was accomplished by gas chromatography–mass spectrometry with multiple reaction monitoring. The main parameters affecting extraction yield and selectivity, such as type and amount of dispersant material, clean-up co-sorbent and extraction solvent were evaluated. The best results were obtained using 1g ginseng, 2g florisil as dispersant sorbent, 0.5g neutral alumina as clean-up co-sorbent, and subsequent extraction with 10mL acetone–n-hexane (5:5, v/v) with assisted sonication and repeated with another 5mL of the same solvent mixture. The method was validated by analysis of ginseng samples fortified at different concentration levels (0.01–0.10mgkg−1). Average recoveries (n=5) ranged from 85 to 95% with relative standard deviation between 2.5 and 11.2%. Spiked blank samples were used as standards to counteract the matrix effect observed in the chromatographic determination. The detection limits ranged from 0.2 to 0.9µgkg−1 in ginseng. The method was applied to the analysis of PCNB and its metabolite residues in commercial ginseng samples.
    Chromatographia 05/2009; 69(9):1113-1117. · 1.37 Impact Factor

Publication Stats

39 Citations
14.96 Total Impact Points

Institutions

  • 2012
    • Zhejiang Academy of Agricultural Sciences
      Zhegang, Jiangxi Sheng, China
  • 2010
    • Chinese Academy of Agricultural Sciences
      • Institute of Plant Protection
      Peping, Beijing, China
  • 2009
    • Institute of Plant Protection, Chinese Academy of Agricultural Sciences
      Peping, Beijing, China