Quantitative determination of p-chlorophenoxyisobutyric acid in blood plasma by gas-liquid chromatography.

A gas-liquid chromatographic method for the determination of p-chlorophenoxyisobutyric (CPIB) acid in blood plasma is described. The substance is extracted from acidified plasma into benzene, the extract is evaporated to dryness and the residue is methylated with an alcohol-free solution of diazomethane and submitted to chromatography on a glass column packed with 3% OV-17. Data on the recovery, reproducibility and sensitivity of the method are given. CPIB acid plasma levels in rats after acute and prolonged treatments with the aluminium salt of CPIB acid (Atherolip) are also presented.