High-pressure liquid chromatography combined with fluorescence detection and solvent extraction for simultaneous determination of coproporphyrins I and III in human urine

A precise and reproducible high-pressure liquid chromatography (HPLC) method for the determination of coproporphyrin I and III isomers (cp isomers) in urine was investigated. The cp isomers were extracted into diethyl ether, the solution was evaporated and the residue dissolved prior to HPLC. The recoveries of both cp isomers were 87.8 +/- 3.2 and 90.0 +/- 2.1% and detection limits (S/N = 3) were 0.07 ng, respectively.