Determination of individual porphyrins in rodent urine using high-performance liquid chromatography following clean-up by anion-exchange chromatography.

We describe a method for the rapid clean-up of rodent urine samples prior to the analysis of porphyrin carboxylic acids by reversed-phase high-performance liquid chromatography (HPLC) with fluorescence detection. A simple pretreatment step using chromatography on a Dowex 1X8 anion-exchange resin effectively removes fluorescent substances that are present in rodent urine and would otherwise interfere with the detection and quantitation of urinary porphyrins by HPLC. Recovery of porphyrins with four to eight carboxyl groups (coproporphyrin to uroporphyrin) averaged 93% using this procedure. The use of this method to determine the amount of individual porphyrins present in the urine of hexachlorobenzene-treated mice is illustrated.