Determination of chlorate and perchlorate in pangasius samples by liquid chromatography tandem mass spectrometry (LC-MS/MS)

The LC-ESI-MS/MS method has been successfully developed for determination of chlorate and perchlorate in pangasius samples. Residues of chlorate and perchlorate in the sample were extracted with a methanolic solution acidified with 1% formic acid. Then, the extract was cleaned with C18 powder, used a normal phase column to separate chlorate and perchlorate, and quantified on an LC-ESI-MS/MS instrument. The method was validated for good specificity, linear calibration curve in the range of 0.0005 - 0.015 mg/L; the limit of quantification (LOQ) was 0.005 mg/kg; the recovery and relative standard deviation was from 91 to 109% and from 6.4 to 9.5% respectively and all met the requirements of SANTE. The method was applied to the real analysis, a total of 427 pangasius fillet samples collected from seafood processing companies. There were 76 samples were detected chlorate equivalent to 18%. The concentration of chlorate ranged from 0.43 to 253 mg/kg.