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Wang M.,Beijing Research Center for Agricultural Standards and Testing | Wang M.,Risk Assessment Laboratory for Agro products Beijing | Jiang N.,Beijing Research Center for Agricultural Standards and Testing | Jiang N.,Risk Assessment Laboratory for Agro products Beijing | And 7 more authors.
Journal of Chromatography A | Year: 2016

A simple and rapid extraction procedure for the simultaneous determination of eight mycotoxins (Alternaria toxins, ochratoxin A, patulin, citrinin) in a variety of fruit matrices has been developed using ultra high performance liquid chromatography coupled to tandem mass spectrometry. The procedure involves a one-step cleanup using homemade solid phase extraction (SPE) cartridges. By comparative evaluation among six various adsorbents (C18, PSA, HLB, MCX, Silica, NH2), the combination of MCX and NH2 was found to provide the most effective cleanup, removing the greatest number of matrix interferences and also allowing the quantification of all analyzed mycotoxins in fruits. The optimized extraction conditions including acidified aqueous acetonitrile and an additional salt-out step using NaCl were employed before SPE cleanup. Method validation was performed by analyzing samples spiked at three levels (LOQ, 2 LOQ and 10 LOQ). Four fruits including apple, sweet cherry, tomato and orange fruits were selected, and accuracy (recovery%), precision (RSD%), limits of quantification (LOQ), linearity and matrix effect were evaluated during validation. Matrix-matched linearity with correlation coefficients ≥0.9921 was established in the range of 5-200ngmL-1 for patulin and 1-200ngmL-1 for other mycotoxins, respectively. Recoveries between 74.2% and 102.4% and relative standard deviations lower than 4.7% were obtained for all tested fruits. The matrix effect observed was low (≤±17%) in all three fruit matrixes with the exception of orange, for which strong ion suppression was observed for alternariol (25.3%), ochratoxin A (31.6%) and citrinin (40.3%). Therefore, matrix-matched calibration was used for a correct quantification in order to compensate for matrix effect. The limits of quantification (LOQ), ranging from 1 to 5μgkg-1 depending on mycotoxins type, were always lower than maximum permitted levels for every regulated mycotoxin by the current European legislation. © 2015 Elsevier B.V.. Source


Xu L.,Beijing Academy of Agriculture and Forestry Sciences | Xu L.,Risk Assessment Laboratory for Agro products Beijing | Li J.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research
International Journal of Environmental Research and Public Health | Year: 2015

Environmental processes and biological community structures change along fluvial gradients within coastal river basins; the accumulation and associated risk of metal contamination would also be expected to change from upstream to downstream reaches. Speciation and degrees of contamination of metals in sediments from the upstream and downstream of river catchments of the southern Bohai Sea were investigated. The mean concentrations of Cu, Zn, Cr, Ni, Cd and Pb from upstream reaches were 82.6, 157, 63.6, 26.6, 0.18 and 24.9 mg/kg, respectively. The mean concentrations of Cu, Zn, Cr, Ni, Cd and Pb from downstream reaches were 38.0, 66.0, 38.9, 18.1, 0.16 and 24.0 mg/kg, respectively. Most of the Cu, Zn, Cr, Ni and Pb in sediments from both the upstream and downstream reaches was mainly associated with the residual fraction. However, Cd was preferentially bound to the exchangeable phase. A cluster analysis was used to study the degree of association between sites, and three distinct clusters were identified in both upstream and downstream sediments. A correlation analysis was conducted to determine the extent of association among metals and showed that metals in sediments from the upstream reaches have more affinity than those in the downstream area. Sediment quality guidelines were used to evaluate potential risks. The risks from Zn, Cr and Ni in the upstream reaches were higher than those from downstream reaches; however, the other three metals (Cu, Pb and Cd) showed opposite results. © 2015 by the authors; licensee MDPI, Basel, Switzerland. Source


Li C.,Beijing Academy of Agriculture and Forestry Sciences | Li C.,Risk Assessment Laboratory for Agro products Beijing | Chen J.,Beijing Academy of Agriculture and Forestry Sciences | Chen J.,Risk Assessment Laboratory for Agro products Beijing | And 11 more authors.
Science of the Total Environment | Year: 2015

The occurrence of 15 antibiotics in soil and manure samples from 11 large-scale greenhouse vegetable production (GVP) bases in Beijing, China was investigated. Results showed that the greenhouse soils were ubiquitously contaminated with antibiotics, and that antibiotic concentrations were significantly higher in greenhouses than in open field soils. The mean concentrations of four antibiotic classes decreased in the following order: tetracyclines (102. μg/kg). >. quinolones (86. μg/kg). >. sulfonamides (1.1. μg/kg). >. macrolides (0.62. μg/kg). This investigation also indicated that fertilization with manure and especially animal feces might be the primary source of antibiotics. A risk assessment based on the calculated risk quotients (RQs) demonstrated that oxytetracycline, chlortetracycline, norfloxacin, ciprofloxacin and enrofloxacin could pose a high risk to soil organisms. These results suggested that the ecological effects of antibiotic contamination in GVP bases and their potential adverse risks on human health need to be given special attention. © 2015 Elsevier B.V. Source


Luan Y.,Beijing Academy of Agriculture and Forestry Sciences | Luan Y.,Risk Assessment Laboratory for Agro products Beijing | Chen J.,Beijing Academy of Agriculture and Forestry Sciences | Chen J.,Risk Assessment Laboratory for Agro products Beijing | And 9 more authors.
Toxins | Year: 2015

A label-free aptamer-based assay for the highly sensitive and specific detection of Ochratoxin A (OTA) was developed using a cationic polymer and gold nanoparticles (AuNPs). The OTA aptamer was used as a recognition element for the colorimetric detection of OTA based on the aggregation of AuNPs by the cationic polymer. By spectroscopic quantitative analysis, the colorimetric assay could detect OTA down to 0.009 ng/mL with high selectivity in the presence of other interfering toxins. This study offers a new alternative in visual detection methods that is rapid and sensitive for OTA detection. © 2015 by the authors; licensee MDPI, Basel, Switzerland. Source


Yang L.,Beijing Research Center for Agricultural Standards and TestingBeijing | Yang L.,Beijing Academy of Agriculture and Forestry Sciences | Yang L.,Risk Assessment Laboratory for Agro products Beijing | Ligang P.,Beijing Research Center for Agricultural Standards and TestingBeijing | And 8 more authors.
International Journal of Agricultural and Biological Engineering | Year: 2015

The suitability evaluation model of the remediation technology of polluted farmland has been constructed by analytic hierarchy process. The evaluation index of remediation technology has been constructed based on the physical and chemical index of farmland, farming system and the characteristic of remediation technology. In addition, the potential risk factors such as the distance of the industrial and mining enterprises, and the economy factors such as repair cost and local economy level have all been considered to construct the suitability evaluation system of the remediation technology of polluted farmland. Shilou town in Beijing was selected for the testing site, with the pollution of cadmium, arsenic and organic matter pollution. Chemical passivation, phytoremediation and biological compost technology were used for restoring the polluted farmland. According to the suitability evaluation model, the phytoremediation technology is suitable for general pollution. And chemical passivation and biological compost technology are more suitable to restore the polluted farmland. The combined remediation technologies of chemical passivation and phytoremediation are more suitable. It can avoid the limit of the one technology, complement the defect for each other and receive more remediation effects. © 2015, Chinese Society of Agricultural Engineering. Source

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