Rapid method for extracting aldrin, dieldrin, and endrin from visceral material.

A simple method is described for purifying aldrin, dieldrin, and endrin from visceral material by using a Celite column. Celite retains all interfering materials including Lipids whereas the chlorinated Insecticides are eluted from the column with n-hexane. This extract can be used directly for gas chromatographic analysis.     

Pathology: studies of chronic toxicity and carcinogenicity.

Safety evaluation of chemicals in use or destined for use by humans is a complex endeavor which requires accurate analytical chemical results, extensive animal studies, and thoughtful interpretation of the data. Especially difficult are attempts to extrapolate the animal data to man. The analytical chemist can base many of his conclusions on data concerning quantity; the toxicologist cannot. The analytical chemist works very hard for an answer, but when he gets it, his task is usually completed. When the toxicologist gets an answer from a given experiment, his problems have just started; he must attempt to interpret the data and, even more difficult, to extrapolate the results of animal data to man. Thus, accurate analysis of chemicals and trace substances in biological tissues form the foundation of the work of the toxicologist. A closer association between analytical chemists and toxicologists should prove beneficial to both and to the progress of science.     

Comparison of dieldrin, lindane, and DDT extractions from serum, and gas-liquid chromatography using glass capillary columns.

Rats were given an oral dose of 14C-labeled chlorinated pesticides to obtain serum containing p,p'-DDT, dieldrin, or lindane. Simple hexane and formic acid-hexane extraction methods, involving pretreatment of the serum with formic acid, were compared by radiometric and by paper chromatographic and gas chromatographic analysis. In vivo binding of chlorinated pesticides to constituents of the serum does not necessarily prohibit their isolation by simple hexane extractions, provided that the extraction is very vigorous and at least 5 min long. Stable emulsions were broken by cooling in liquid nitrogen or Dry Ice-acetone. The hexane extraction method described yields quantitative recovery of the pesticides studied, whereas the formic acid-hexane method is quantitative for p,p'-DDT, 93% for dieldrin, and 89% for lindane. Gas chromatographic comparison of both methods, using human serum, shows that the hexane method extracts 16% more beta-BHC, 7% more dieldrin and HCB, and 4% more p,p'-DDE from serum than does the formic acid-hexane method. The difference for p,p'-DDT is not significant. Gas chromatography with glass capillary columns and an all-glass solids injection system yielded detection limits as low as 15 fg. Data show that the use of an internal standard considerably improves the precision of quantitation.     

Comparison of studies on saccharin and sodium nitrite.

A review of long term animal studies of saccharin and sodium nitrite was undertaken to assess the effect of variability of selected protocol elements on the results obtained. These elements were divided into 4 general categories: design, including selection of test animals, basal diet, dosage form and doses of test substance, route of administration, and duration of exposure; observations, including gross observations during life and at necropsy, clinical tests, and histopathology; performance, including conduct of the test and animal husbandry; and analytical procedures, including chemical and statistical analyses. Because many of the protocol elements are not fully discussed in study reports, it was often impossible to determine what actually had been done. The review of various saccharin studies suggests that bladder tumors resulted following in utero exposure. In utero exposure with sodium nitrite did not appear to cause reticuloendothelial changes. The numerous variations in protocol elements in the nitrite studies precluded identification of a prime element responsible for the variation in reticuloendothelial changes observed. It can be concluded from this review that achievement of reproducibility in long term studies requires minimal variation of protocol elements for the new study.