Conjugated dienes detected in tissue lipid extracts by second derivative spectrophotometry.

By studying lipid peroxidation induced by tetrachloromethane in rat liver microsomal PUFA, it has recently been shown that the primary products formed are conjugated diene hydroperoxides having either cis, trans (c,t) or trans,trans (t,t) stereochemistry. Both c,t and t,t hydroperoxidienes present distinct absorbances at 242 nm and 233 nm, respectively. The reaction is kinetically controlled in relation to the total H-atom donating ability of the cell environment. These results have been confirmed in vivo and in vitro experiments performed under different experimental conditions. The need for a precise and objective method to detect conjugated diene signals, the inherent difficulties with current techniques, and the availability of new spectrophotometric techniques have led us to devise a new method based on the second derivatization of the spectrum.