Abstract: A double depuration-gas chromatography (DDGC) method was developed for the simultaneous determination of residues of hexachlorocyclohexanes (BHCs), dichlorodiphenyltrichloroethanes (DDTs) and indicator polychlorinated biphenyls (PCBs) in eggs and egg products. Samples were extracted with acetonitrile followed by double purification with concentrated sulfuric acid and calcined hydrotalcite. Then the analytes were analyzed by GC and quantified with an external standard method. Results showed that compared with the traditional sulfonation method, more thorough extraction and higher purification efficiency of the target analytes with less interferences were achieved by double-purification with concentrated sulfuric acid and calcined hydrotalcite. Good linearities were obtained for four BHCs, two DDTs, and seven PCBs with correlation coefficients greater than 0.999 in the range of 10–200 μg/L. The limits of detection (LODs) (RSN = 3) and limits of quantitation (LOQs) (RSN =10) of the GC method were 1.12–3.89 and 3.73–12.97 μg/kg, respectively. The recoveries of these analytes from liquid egg, preserved eggs and salted eggs ranged from 78.04% to 105.05%, with relative standard deviation (RSD) ranging from 1.28% to 7.55% at three spiked levels of 10, 20, and 100 μg/kg. The method was simple, rapid, accurate and sensitive, and it was suitable for rapid detection of PCBs, BHCs and DDTs residues in eggs and egg products.

Key words: eggs, egg products, hexachlorocyclohexanes (BHCs), dichlorodiphenyltrichloroethanes (DDTs), indicator polychlorinated biphenyls (PCBs), gas chromatography (GC)