Determination of Organochlorine Levels in Antarctic Skua and Penguin Eggs by Application of Combined Focused Open-Vessel Microwave-Assisted Extraction, Gel-Permeation Chromatography, Adsorption Chromatography, and GC/ECD

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Abstract
Levels of organochlorines (PCBs, DDT, toxaphene, chlordane, hexachlorobenzene (HCB), hexachlo-rocyclohexanes (HCHs), dieldrin, Q1) were determined in eggs of both penguins (Adelie Pygoscelis adeliae, Chinstrap Pygoscelis antarctica, Gentoo Pygoscelis papua) and skuas (South Polar Skua Catharacta maccormicki, Brown Skua Catharacta antarctica lonnbergi, Mixed Pair Skua Catharacta maccormicki x lonnbergi) from the Antarctic. Focused open-vessel microwave-assisted extraction (FOV-MAE) was performed for the extraction of entire, partly lyophilised eggs (approx. 50 g). After gel-permeation chromatography (GPC) and adsorption chromatography on deactivated silica gel, the quantitation was performed by GC/ECD on two capillary columns of different polarity. Compounds of technical toxaphene (CTTs) were determined after separation of the PCBs. The sample clean-up method was validated with certified reference material SRM 1588. In general, skua eggs revealed higher organochlorine levels than penguin eggs. Main contaminants in skua eggs were p,p'-DDE, PCB 153, and PCB 180 with levels about 10 − 350 μg/kg wet weight without shell (ww). Eggs of penguins were topped by levels of hexachlorobenzene (HCB) and p,p'-DDE (2 − 22 μg/kg ww), respectively. In skua eggs, the most abundant CTTs were B9-1679 (Parlar #50) > B8-1413 (Parlar #26) > B9-1025 (Parlar #62) > B8-1412, the levels were about 1-20 μg/kg ww. In penguin eggs, however, the order was B8-1413 (Parlar #26) > B9-1679 (Parlar #50) > B8-1412 > B9-1025 (Parlar #62), and the levels ranged from 0.02 − 0.8 μg/kg ww. A so far unknown heptachloro compound labelled Q1 caused an abundant peak in some samples. Levels of Q1 (2 − 126 μg/kg ww in skua eggs and 0.3 − 1.2 μg/kg ww without shell in penguin eggs) were estimated relative to the ECD response factor of trans-nonachlor.