We report a new method for obtaining urinary and faecal porphyrin excretion patterns in human porphyrias based
on fast atom bombardment mass spectrometry (FAB-MS). Porphyrins were esterified and extracted from urine or
faeces as their methyl esters for analysis by FAB-MS. The protonated pseudo-molecular ion [M + H] ÷ observed for
each porphyrin is characteristic of that porphyrin, thus allowing a mixture of porphyrins to be analysed without the
need for chromatographic separation. By using tandem MS, identification and characterisation of unknown
porphyrins can be achieved. The urinary and faecal porphyrin excretion patterns from various porphyric patients
obtained by FAB-MS are in good agreement with those analysed by TLC or HPLC methods. © 1997 Elsevier Science
B.V.