Novel cleanup method for quantitative gas chromatographic determination of trace amounts of Di-2-ethylhexyl phthalate in fish lipid.

A new, simple, and rapid cleanup procedure is described for di-2-ethylhexyl phthalate (DEHP) residues in fish lipids. Extracted are chromatographed on small alumina:sulfuric acid-impregnated alumina (layered) columns after gel permeation chromatography of the fish lipid extracts on BioBeads SX-3. Quantitative analyses were carried out by electron capture gas chromatography using 2 columns. Spiked DEHP recoveries varied from 79.3% in mackerel to 86.3% in herring. DEHP concentrations were determined in plaice, eel, redfish, herring, cod, and mackerel tissues and ranged from trace (less than 0.001 microgram/g) to approximately 10 microgram/g (wet wt basis). Ethanolic KOH saponification of the purified DEHP fraction, resulting in the disappearance of the DEHP peak, was used as a confirmatory test. Limited studies with dibutyl, di-n-heptyl, and diethyl phthalates suggest that the method can be made more versatile.