The analysis of quaternary ammonium compounds in human urine by direct inlet electron impact ionization mass spectrometry.

An accurate and rapid screening test for nine quaternary ammonium compounds (suxamethonium chloride, pancuronium bromide, ambenonium chloride, benzethonium chloride, distigmine bromide, methylbenactyzium bromide, neostigmine bromide, propantheline bromide and pyridostigmine bromide) by direct inlet electron impact ionization mass spectrometry (DI/EI-MS) was investigated. Each compound was extracted from urine as an ion pair with KI3 into dichloromethane. The reliability of the identification of these compounds was verified by the mass chromatographic analysis of their characteristic fragment ions. The analysis of these drugs by DI/EI-MS could be performed within 5 min. The detection limits were between 20-150 ng/ml for the nine compounds. This method appears to be efficient, rapid and suitable as a screening procedure for the quaternary ammonium compounds found in urine.