Chlordene epoxide was detected in the range of 0.04 to 0.27 ppm in the edible portion of 3 catfish samples during the analysis of 36 fish samples by electron capture gas-liquid chromatography (GLC) for pesticide and industrial chemical residues. Two of these catfish samples were from suppliers in Louisiana and the third was from a Texas supplier. Chlordene was also present; the amount of chlordene epoxide in the 3 samples averaged 46% of the amount of chlordene present. The epoxide was identified by comparison of the mass spectra and the CLC retention times of the samples with reference material prepared in this laboratory.

Four alteration products of malathion have been observed in crop extracts of rice, which may not be readily identifiable in a typical gas chromatographic-mass spectrometric (GC-MS) analysis of the residues. Extracts of rice containing malathion and several related compounds were analyzed on gasliquid chromatographic (GLC) columns of different polarities. The methyl ethyl succinate ester of malathion co-elutes with malaoxon from a nonpolar GLC column. Retention data and GC-MS analysis indicate the presence of 3 previously reported compounds. Evidence was obtained for a fourth compound, O-methyl O-ethyl S-(l,2-bis-carbethoxy) ethyl phosphorodithioate, apparently resulting from the environmental alteration of malathion.

Morphine in injectable preparations mar undergo reaction with bisulfite when this is used as an antioxidant in the formulation. A simple chromatographic procedure has been developed for the separation of morphine from its oxidation products and from the morphine-bisulfite interaction products. Neutral or acidic impurities are removed from a pH 4.3 buffered sample by elution of a partition chromatographic column with ether. An ether solution of di-(2- ethylhexyl) phosphoric acid is then used to elute the morphine as the cationic component of the ion pair. This fraction is extracted with dilute sulfuric acid to dissociate the ion pair and transfer the morphine to the acid solution for spectrophotometric determination. Multiple analyses of a commercial morphine sulfate formulation gave 101.2±0.3% of declared. Assays by 5 analysts of another commercial preparation and a laboratory preparation gave, respectively, an average of 99.6±2.7% of declared and an average recovery of 90.4±0.5%. The latter, containing 7 mg bisulfite/ml, or 7 times as much as the commercial formulations, shows significant bisulfite-induced decomposition.