Identification of carpronium chloride and its metabolite in human urine by field desorption mass spectrometry using deuterium labelling.

The identification of carpronium chloride and a metabolite in human urine has been performed by means of field desorption mass spectrometry using deuterium labelling. Essential points in this study are the simultaneous administration of a deuterium labelled drug ([2H9]carpronium chloride), a purification procedure by ion pair extraction with an iodine reagent, and the use of paper electrophoresis to examine the degree of clean-up. The field desorption mass spectra of the purified extracts obtained from sample urine gave a characteristic pattern resulting from the carpronium cation (m/z 160, m/z 169) and a metabolite of the N-(3-carbohydroxypropyl)trimethyl ammonium cation (m/z 146, m/z 155).