Reduced recovery of dieldrin residues-a shortcoming of sulfuric cleanup of biological samples.

Reduced quantitative recovery of dieldrin (1, 2, 3, 4, 10, -10-hexachloro-6, 7-epoxy-1, 4, 4a, 5, 6, 7, 8, 8a-octahydro-1, 4-endo, exo-5, 8-dimethanoaphthalene) while using concentrated sulfuric acid for the cleanup of the extracted samples, has been investigated by gas-liquid chromatography and infrared (IR) spectroscopy. In vitro studies have shown that the servere breakdown in the recovery of dieldrin can be checked if 65% (v/v) H2SO4 is used as opposed to the concentrations greater than 70% sulfuric acid, the epoxide ring attached to the norbornene nucleus of dieldrin undergoes rearrangement to form keto-dihydroaldrin.