Application of capillary electrophoresis mass spectrometry to the analysis of urine samples from animals and man containing paracetamol and phenacetin and their metabolites

Capillary electrophoresis, in combination with electrospray mass spectrometry (CE-ESMS), has been applied to the analysis of phenacetin and paracetamol and its metabolites in freeze dried urine, and solid phase extracts of urine, following administration to rat and man, Using CE-ESMS the detection of 2 pg of d(3)-paracetamol on column was possible. Phenacetin, paracetamol and paracetamol glucuronide and sulfate were all readily detectable in the samples, The CE-ESMS method was also used to determine the extent of deacetylation/reacetylation of d(3)-acetyl-labelled paracetamol in vivo.