Porphyrin profiles in blood, urine and faeces by HPLC/electrospray ionization tandem mass spectrometry

Abstract A high‐resolution high‐performance liquid chromatography/electrospray ionization quadrupole time‐of‐flight tandem mass spectrometry method is described for the analysis of porphyrins in blood, urine and faeces. The gradient elution reversed‐phase HPLC system using acetonitrile–methanol–1 m ammonium acetate/acetic acid buffer (pH 5.16) as gradient solvent mixtures was able to separate all porphyrin metabolites, including the type I and type III isomers of uroporphyrin, hepta‐, hexa‐ and penta‐carboxylic acid porphyrins and coproporphyrin. The porphyrins were positively identified by the protonated molecules [M+H] + and further characterized by tandem mass spectrometric analysis with each porphyrin giving a characteristic collisioninduced dissociation product ion spectrum. The mass chromatograms obtained by HPLC/ESI MS are useful for the differential diagnosis of the porphyrias, since each type of porphyria has a typical porphyrin excretion pattern. Copyright © 2006 John Wiley & Sons, Ltd.