title: Direct gas chromatograph-mass spectrometer connection of glass capillary columns for the analysis of serotonin and metabolites by selective ion monitoring.
abstract: A direct connection system that requires no modifications to either the gas chromatograph or the mass spectrometer is described for the coupling of glass capillary columns to a commercial mass spectrometer. Vacuum-tight connections can be readily achieved with standard 1/16-in. fittings and septum discs. The system can be operated with column outlet helium flow-rates of 1.5-2 ml/min at ion source pressures of 2-5 - 10(-5) mmHg. Although an injector splitter of our own design has been used, the initial test results obtained with a splitless injection method based on the use of a solids injection syringe together with a packed column injector assembly indicate the feasibility of developing a totally splitless and connection system that is simple to use. The system has been applied to the detection of the pentafluoropropionyl derivatives of serotonin, methoxytryptamine, methoxytryptophol and 5-hydroxytryptophol by selective ion monitoring techniques. Column performances under both sets of conditions (gas-liquid chromatography alone and combined with mass spectrometry) are compared and the evaluation of direct versus indirect coupling showed yields of the order of 50% through the molecular separator.
mesh_terms: D002849:Chromatography, Gas; D005898:Glass; D013058:Mass Spectrometry; D008722:Methods; D012701:Serotonin / Q000031:analogs & derivatives / Q000032:analysis* / Q000378:metabolism
chemical_list: D012701:Serotonin