Laboratory of Quality and Safety Risk Assessment for Agro products Chengdu

Chengdu, China

Laboratory of Quality and Safety Risk Assessment for Agro products Chengdu

Chengdu, China
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Hou X.,Sichuan Academy of Agricultural science | Hou X.,CAS Chengdu Institute of Organic Chemistry | Hou X.,Laboratory of Quality and Safety Risk Assessment for Agro products Chengdu | Wu Z.-J.,CAS Chengdu Institute of Biology | And 3 more authors.
Rapid Communications in Mass Spectrometry | Year: 2017

Rationale: In addition to their biological properties, oxovanadium complexes have been widely applied as catalysts because of their excellent catalytic-oxidation capability. Recently, monometallic oxovanadium(IV) complexes have been used as catalysts in the electrophilic trifluoromethylation of silyl ketene imines. The study of catalysts can contribute to an understanding of the reaction mechanism. Methods: Six monometallic oxovanadium(IV) complexes were analyzed by electrospray ionization time-of flight mass spectrometry (ESI-TOFMS), and collision-induced dissociation mass spectrometry (CID-MS) experiments were conducted for selected cations [M]+ of oxovanadium(IV) complexes as well as a deuterium-labeled complex. Different collision gases were used to understand the source of the O2 and H2O engaged in the gas-phase ion-molecule reaction. Results: The oxovanadium(IV) complexes formed [M]+ ions by loss of an electron, with [M + 14]+ ions being formed from [M]+ by loss of H2O and addition of O2. The fragmentation pathways of the [M]+ cations were further studied by ESI-MS/MS, and several ions produced by gas-phase ion-molecule reactions were detected and characterized, including vanadium-oxo, −peroxo and derivatives. Conclusions: Several unexpected ions were detected, including [M]+, [M + 14]+ and ions produced from gas-phase ion-molecule reactions. The study has contributed to the understanding of the structure and character of oxovanadium(IV) complexes, and it could facilitate the design of new oxovanadium catalysts and an understanding of their reaction mechanism. Copyright © 2017 John Wiley & Sons, Ltd.


Hou X.,Sichuan Academy of Agricultural science | Hou X.,Laboratory of Quality and Safety Risk Assessment for Agro products Chengdu | Lei S.R.,Sichuan Academy of Agricultural science | Lei S.R.,Laboratory of Quality and Safety Risk Assessment for Agro products Chengdu | And 4 more authors.
Brazilian Journal of Pharmacognosy | Year: 2016

A method for analysis of 101 pesticide residues in tea leaves was developed and validated for the first time.Pure acetonitrile was used as extraction solvent rather than acetonitrile after matrix hydration based on the amount of co-extracts and recoveries performance.During clean-up procedure, primary-secondary amine/graphitized carbon black (500 mg) was selected, which exhibited outstanding properties in clean-up capabilities and recoveries of pesticides comparing to primary-secondary amine/graphitized carbon black (250 mg), NH2-Carbon and TPT absorbents.The method was validated employing gas chromatography coupled to tandem mass spectrometry at the spiked concentration levels of 0.050 and 0.100 mg kg-1.For most of the targeted pesticides, the percent recoveries range from 70 to 120%, with relative standard deviations <20%.The linear correlation coefficients (r2) were higher than 0.99 at concentration levels of 0.025-0.250 mg kg-1.Limits of quantification ranged from 1.1 to 25.3 µg kg-1 for all pesticides.The developed method was successfully applied to the determination of pesticides in tea leaf samples. © 2016 Sociedade Brasileira de Farmacognosia.


Mao J.,Laboratory of Quality and Safety Risk Assessment for Agro Products Chengdu | Lei S.,Laboratory of Quality and Safety Risk Assessment for Agro Products Chengdu | Xiao D.,University of Sichuan | Fu C.,Laboratory of Quality and Safety Risk Assessment for Agro Products Chengdu | And 2 more authors.
Food Control | Year: 2014

The immunoaffinity column cleanup method coupled with HPLC separation and fluorescence detection is still one of the most frequently used quantitative methods for routine analyses of AFM1. In this study, aflatoxin M1 (AFM1) was quantified with a chromatography column packed with 2.6μm core-shell particles on a conventional HPLC. A large volume of solvent (100μL) was injected into the highly efficient column without any noticeable reduction in separation performance with the help of stepwise gradient elution. The instrumental conditions were optimized by response surface analysis methodology (RSM) with a three-level three-factor Box-Behnken design. The use of core-shell columns on conventional HPLC for AFM1 analysis under the optimized instrumental conditions leads to increased analytical performance compared with traditional totally porous columns without the heavy costs associated ultra-high-pressure instruments. Moreover, the improved instrumental sensitivity enables simplified sample preparation by avoiding any solvent replacement. The method could be easily applied to enhance the sensitivity of HPLC-FLD for AFM1 analysis that is based on isocratic elution and is more widely used. The method was successfully applied to 40 raw milk samples collected in summer from 20 cattle ranches located in two different provinces in southwestern China. © 2014 Elsevier Ltd.


Mao J.,Academy of Agricultural Science | Mao J.,Laboratory of Quality and Safety Risk Assessment for Agro products Chengdu | Mao J.,University of Sichuan | Lei S.,Academy of Agricultural Science | And 4 more authors.
Food Control | Year: 2013

Ochratoxin A (OTA) is a mycotoxin commonly present in red wine and other foodstuffs. It is widely studied due to its nephrotoxic, immunotoxic, teratogenic and carcinogenic effects. Nowadays, liquid chromatography is the main method for OTA analysis. With the recent development on the column technology, core-shell columns were commercialized in recent years. It is with high performance while maintain low back pressure thus could be used on conventional HPLC instrument. However, as current conventional benchmark high-performance liquid chromatographs were not initially designed for the recently developed high-efficiency packed columns, the HPLC-FLD parameter should be carefully investigated. In this work the performance of chromatography column packed with 2.6 μm core-shell particles on conventional benchmark HPLC were investigated. Parameters including flow rate, mobile phase composition (volume fraction of ACN in water), temperature, response time, sampling frequency, and injection volume for quantitative analysis of OTA in red wines were investigated in detail. The results show that core-shell column is more effective and faster to be operated on conventional HPLC than other total porous particle packed column. Optimized conditions provided a method for the separation of OTA in less than 5 min, with the limit of detection (LOD) 0.0025 μg/L and the limit of quantification (LOQ) 0.0083 μg/L in the sample, respectively. The developed method was validated with red wine samples with OTA concentrations ranging from 0.0028 to 0.0437 μg/L. The use of a core-shell column allows highly efficient, sensitive, and accurate determination of OTA with an outstanding sample throughout. © 2013 Elsevier Ltd.

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