Normal-phase high-performance liquid chromatographic determination and identification of aldrin, dieldrin, and DDTs in eggs

A method for the routine monitoring of residual aldrin, dieldrin, pp′-DDT, op′-DDT, pp′-DDE, and pp′-DDD in eggs by high- performance liquid chromatography (HPLC) with a photo-diode array (PDA) detector is described. The lipids extracted from a whole egg are cleaned by a solid-phase extraction (SPE) ISOLUTE NH2 column with a diethyl ether-hexane (5:95, v/v) eluent. The HPLC separation is carried out using a normal-phase (LiChrosorb NH2) column, a heptane-hexane eluent (97:3, v/v), and a PDA detector. The average recoveries from fortified target compounds (0.1, 0.2, 0.3, and 0.4 μg/g, respectively) are ≥ 83%, with standard deviations (SDs) between 2 and 5%. The interassay variabilities and their SDs are ≤ 4.8% and ≤ 0.7%, with intra-assay variabilities of 2.1-3.3%. The limits of determination for these compounds range from 0.04 to 0.08 μg/g.