Direct quantification of coproporphyrins and uroporphyrins in urine by derivative synchronous fluorescence spectroscopy.

The second-derivative synchronous fluorescence spectroscopic technique is applied to the simultaneous and direct assay of coproporphyrins and uroporphyrins in human urine. This technique resolves the overlapping conventional spectra, obviating the need for pre-analysis sample separation techniques, and measurements can be made in a single scan. The amplitudes of the derivative peaks are linearly related to uroporphyrin (0.4 to 300 micrograms/L) and coproporphyrin (0.4 to 250 micrograms/L) concentrations. The detection limit for both porphyrins is 0.1 microgram/L. Analytical recoveries range between 98 and 101%. Within- and between-assay CVs are reported. Results for 24-h urine specimens correlated well with those obtained by an extraction-ion-exchange chromatography combined method. The proposed method is inexpensive and requires no sophisticated detection equipment.