Determination of mercaptans by negative ion mass spectrometry

Research by West Germany's Institut fuer Forschung und Entwicklung shows that negative-ion mass spectrometry using a modified conventional ion source with a hot cathode and a sample pressure of 10/sup -4/ torr provides a viable direct method for the quantitative analysis of individual mercaptans in hydrocarbon solvents without the need for prior separation. The limit of detection is 10 ppM of individual mercaptans. The negative-ion intensities related to a mercaptan internal standard are independent of the hydrocarbon solvent and the gas pressure in the ion source.