DETERMINATION OF DETERMINING POLYCHLORINATED BIPHENYLS PCBS IN FOOD BY BY MASS SPECTROMETRY (MS) AND GAS CHROMATOGRAPHY (GC) WITH ELECTRON CAPTURE DETECTION (ECD)

Abstract

      A simple, sensitive method for determining polychlorinated biphenyls (PCBs) including non dioxin-like PCBs (PCB 28, 52, 101, 138, 153, 180) in food has been developed. The method bases on liquid-liquid extraction with organic solvents, a series of clean-up steps with acid and solid phase extraction (SPE) using florisil for the pretreatment and analysis by gas chromatography (GC) with electron capture detection (ECD) aSnd mass spectrometry (MS). Sample preparation conditions, such as the extraction solvent, SPE operational parameters (such as elution solvent, elution volume) and instrument conditions, such as GC column, oven temperature programs, carrier gas flow rate, were optimized. The congener specific averages of recoveries were 80.3 - 109.2 % with the relative standard deviation (RSD%) of 2.62 - 7.21 % (n = 6) at spiking levels of maximum residue limits (MRLs): MRL/2, MRL, 2MRL. Method quantification limits were in the 0.40 - 0.83 μg/kg range as determined by GC-ECD and 1.30 - 4.16 μg/kg range by GC-MS. The linearity of the method was good with a linear correlation coefficient (R2) of 0.996. The method was applied to the analysis of samples of fish purchased at the Hanoi local market.

 Keywords: PCBs, non dioxin-like PCBs, fish, SPE, determination