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Zhuo L.,Fuzhou University | Zhuo L.,Quality Inspection Institute of Quanzhou | Yin Y.,Fuzhou University | Fu W.,U.S. Center for Disease Control and Prevention | And 6 more authors.
Food Chemistry | Year: 2013

This paper describes the use of QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) for the extraction, cleanup and detection of 10 paralytic shellfish toxins (PSP) in sea food by HILIC-MS/MS with positive ESI. Matrix matched calibration standards were used to compensate for matrix effects. The toxins were extracted with acetonitrile/water (90:10, v/v) containing 0.1% formic acid and cleaned by HLB and GCB sorbents. Qualitative and quantitative detection for the analytes were carried out under the multiple reaction monitoring (MRM) in positive ionization mode after chromatography separation on a TSK-gel Amide-80® column (150 mm × 2.0 mm × 3 μm). Studies at three fortification levels for the toxins in the range of 8.1-225.5 μg/kg gave mean recoveries from 71.3% to 104.6% with relative standard deviation (RSD) ≤ 15.8%. The limit of detection (LOD) was below the recommended regulatory limit of 170 μg STXequ./kg and the proposed method fully meets the needs of daily monitoring. © 2012 Elsevier Ltd. All rights reserved. Source


Zhuo L.,Fuzhou University | Zhuo L.,Quality Inspection Institute of Quanzhou | Fu W.,U.S. Center for Disease Control and Prevention | Yang Y.,Quality Inspection Institute of Quanzhou | And 6 more authors.
Rapid Communications in Mass Spectrometry | Year: 2014

RATIONALEA method has been developed for simultaneous determination of the toxins OA, DTX-1, AZA-1, AZA-2 and AZA-3 in various aquatic products as these can cause diarrhoetic shellfish poisoning (DSP) in humans, an intoxication characterized by vomiting and diarrhea. METHODSSeparation of the toxins was achieved on a C18 column (150 mm × 2.1 mm, 3.5 μm) using an acetonitrile/water gradient with formic acid as an eluent modifier. Electrospray ionisation (ESI) in negative mode was used to generate the molecule related ion [M-H]-, for OA and DTX-1, while ESI in positive mode was used to generate the molecule related ion [M+H]+ for AZAs. Samples were extracted with 80% methanol, followed by partitioning with ethyl acetate, purified on a Poly-Sery MAX cartridge and finally analyzed by LC/ESI-MS/MS in the multiple reaction monitoring (MRM) mode. RESULTSThe limit of detection (LOD) and limit of qualification (LOQ) of the method were in the range of 0.02-0.79 μg/kg and 0.07-2.64 μg/kg in Scomberomorus niphonius, blood clam and oyster, respectively, recoveries of the toxins at three fortification levels ranged from 71.3% to 104.8% with relative standard deviation from 1.0% to 12.5%. The calibration curves were well linear between the LC peak area of the selected ion pair and the concentration of the toxins, with the correlation coefficient over 0.99. CONCLUSIONSThe method was sufficiently sensitive to permit the determination of the toxins DSP and AZA in sea food. Copyright © 2014 John Wiley & Sons, Ltd. Source

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