Sandwich-type extraction column with on-line sulphuric acid treatment for the determination of organochlorine compounds in vegetable oil or oil seeds by gas chromatography with electron-capture detection

Abstract

An effective clean-up technique for the determination of hexachlorobenzene (HCB), α-hexachlorocyclohexane (HCH), β-HCH, γ-HCH (lindane), heptachlor, heptachlor epoxide, aldrin, 2,4′-DDE, 4,4′-DDE, 2,4′-DDT, 4,4′-DDT and endosulfan in vegetable oils and oil seeds by gas chromatography with electron-capture detection is described. The separation of these organochlorine pesticides from normally co-extracted fatty material of plant origin was achieved by the use of a new “sandwich”-type extraction column, allowing adsorption of polar matrix interferences on Florisil, Extrelut and sodium sulphate and “on-line” degradation of usually at least partially co-eluting triglycerides with sulphuric acid in a single step. Quantification down to the 1–5 ppb level was performed by external or internal standard calibration using pentachlorobenzene and Mirex as internal standards.