Food Laboratory

Nanjing, China

Food Laboratory

Nanjing, China

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Meng W.,East China University of Science and Technology | Guo Z.,CAS Dalian Institute of Chemical Physics | Shen W.,Food Laboratory | Shen C.,Food Laboratory | And 5 more authors.
Chinese Journal of Chromatography (Se Pu) | Year: 2012

A simple and efficient method based on a novel solid phase extraction (SPE) cartridge and ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS/ was developed for the determination of clenbuterol residue in pork. The minced pork sample was ultrasonically extracted by 5% (v/v) perchloric acid and centrifuged at 10 000 r/min for 15 min, then the supernatant was purified by an SMCX cartridge; which is a novel SPE column based on homemade silica matrix with two mixed modes of reversed-phase and strong cation exchange; for the selective enrichment and purification of the analyte. The linear range of the method was 0.25-50 μg/kg with a correlation coefficient of 0.9982. The average recoveries ranged from 62.2% to 72.0% at the three spiked levels of 1.25, 12.5 and 50 μg/kg with the relative standard deviations (RSDs) between 4.2% and 6.1%. The limit of detection (S/N=3) was 0.05 μg/kg. The method is simple, fast and can be extended to enrich and determine β-agonist drugs. © 2010 Editorial Office of Chinese Journal of Chromatography, Dalian Institute of Chemical Physics, CAS.

PubMed | University of Maryland Baltimore County, University of Tehran, Food Laboratory, Qiagen and 2 more.
Type: | Journal: Veterinary microbiology | Year: 2016

Viral haemorrhagic septicaemia virus (VHSV), a member of family Rhabdoviridae and genus Novirhabdoviridae, causes mortality in numerous marine and freshwater hosts located in northern hemisphere. To evaluate the genetic diversity of VHSV from the North and South West of Iran, the sequences of a 1483bp nt region of the glycoprotein gene were determined for four Iranian isolates. These sequences were analysed to evaluate their genetic relatedness with 86 worldwide isolates representing the four known genogroups of VHSV. Phylogenetic analysis by nucleotide sequences showed that all the VHSV isolates studied were closest related to the 19 fresh water strains from Germany grouped within the European genogroup Ia-2. This finding indicates that Iranian VHSV most likely was introduced to Iran by the movement of contaminated fish fry from a source in Europe.

Zhang R.,Food Laboratory | Shen W.,Food Laboratory | Wei X.,China Pharmaceutical University | Zhang F.,East China University of Science and Technology | And 5 more authors.
Analytical Methods | Year: 2016

A simple and rapid gas chromatography-mass spectrometry (GC-MS) method was developed and validated for the simultaneous determination of α-, β-, γ- and δ-tocopherols and α-, β-, γ- and δ-tocotrienols in vegetable oils. In this study, tedious sample pretreatments like saponification and derivatization, which are commonly used in previously published related methods, were not adopted. Tocopherols and tocotrienols were isolated from oil samples by ultrasonic extraction with methanol, then centrifuged and the supernatant was directly injected into the GC-MS system for analysis. The results showed that α-, β-, γ- and δ-tocopherols and α-, β-, γ- and δ-tocotrienols were well separated within 14 minutes. The instrumental limits of detection and quantification ranged from 0.3 to 2.5 ng mL-1 and from 1.0 to 8.3 ng mL-1, respectively. Calibration curves were well correlated (r2 > 0.99) within the concentration range of 10 to 1000 ng mL-1 for all eight compounds. Recovery tests were carried out by spiking virgin olive oil with standards at three concentration levels (10, 50 and 250 mg kg-1), in which the average recoveries (n = 6) varied from 83.7% to 117.2%, with relative standard deviations ranging between 1.9% and 7.5%. The proposed method proved to be simple, sensitive and accurate, and was successfully applied to the determination of tocopherols and tocotrienols in vegetable oils. ©2016 The Royal Society of Chemistry.

Wei X.,China Pharmaceutical University | Wei X.,Food Laboratory | Shen W.,Food Laboratory | Yu K.,Food Laboratory | And 8 more authors.
Chinese Journal of Chromatography (Se Pu) | Year: 2016

The gas chromatography-mass spectrometric (GC-MS) method with two different ionization techniques, electron impact (EI) and positive chemical ionization (PCI), have been developed for the simultaneous determination of three sterenes in olive oil. The olive oil sample was dissolved in petroleum ether, followed by cleanup on a silica gel column and finally analyzed by GC-EI/MS and GC-PCI/MS in selected ion monitoring mode. The quantitation was performed by internal standard calibration with cholesta-3, 5-diene as internal standard. These two methods were compared in terms of linearity, accuracy, precision and sensitivity. Good linearities were obtained with correlation coefficients (r) higher than 0.999 for campesta-3, 5-diene in the range of 0.024 to 0.48 mg/L, stigmasta-3, 5, 22-triene in the range of 0.02 to 0.50 mg/L and stigmasta-3, 5-diene in the range of 0.03 to 0.75 mg/L. The accuracy test was carried out at three spiked levels in extra virgin olive oil. The average recoveries ranged from 88.7% to 99.5% (EI) and 87.1% to 109.2% (PCI), with relative standard deviations (RSDs, n=6) not higher than 8.3%. Limits of quantification (LOQs, S/N=10) were 0.03 mg/kg (EI) and 0.03-0.10 mg/kg (PCI). Comparative analysis showed a large number of fragment ions could be obtained in EI mode while quasi-molecular ions or other adduct molecular ions were the most abundant ion formed in the PCI mode. Besides, PCI has a better selectivity than EI when applied to real samples. In conclusion, these two ionization techniques are complementary and alternative in the routine analysis of sterenes in olive oil.

Xia G.,China Pharmaceutical University | Shen W.,Food Laboratory | Yu K.,Food Laboratory | Wu B.,Food Laboratory | And 5 more authors.
Chinese Journal of Chromatography (Se Pu) | Year: 2014

A method was developed for the determination of four insecticide residues in honey and royal jelly by gas chromatography-negative chemical ionization mass spectrometry (GC- NCI / MS). The honey and royal jelly samples were treated with different preparation methods as the result of the different components. The honey sample was extracted with ethyl acetate and cleaned up with primary second amine, and the royal jelly sample was extracted with acetonitrile-water (1 :1, v / v), and cleaned up with a C18 solid-phase extraction column. Finally, the extracts of the honey and royal jelly were analyzed by GC-NCI / MS in selected ion monitoring (SIM) mode separately. External standard calibration method was used for quantification. The linearities of calibration curves of the four insecticides were good with the correlation coefficients greater than 0. 99 in the range of 50-500 μg / L. The limits of the detection (LODs) of the four insecticides were in the range of 0. 12-5. 0 μg / kg, and the limits of the quantification (LOQs) were in the range of 0. 40-16. 5 μg / kg. The recoveries of the four insecticides spiked in honey and royal jelly at three spiked levels (10, 15 and 20 μg / kg) were in the range of 78. 2% -110. 0%, and the relative standard deviations (RSDs) were all below 14%. The sensitivity and selectivity of this method were good with no interfering peaks. The proposed method is simple, quick and effective to analyze the four insecticide residues in honey and royal jelly.

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