A method of operating a gas chromatograph-mass spectrometer (GC-MS) comprising a GC column for separating analytes of a sample, a GC oven and a mass spectrometer comprises: providing a conduit extending between the GC oven and the mass spectrometer such that a conduit interior volume is contiguous with an interior volume of the GC oven; routing the GC column through the GC oven and conduit interior volume to an ion source of the mass spectrometer; providing a flow of temperature regulated air or gas between a fan or blower of the gas chromatograph and the conduit interior volume; introducing the sample into the GC column; controlling the temperature of the GC oven interior volume and the conduit interior volume so as to facilitate analyte separation within the GC column and transfer of the separated analytes to the mass spectrometer; and analyzing the separated analytes with the mass spectrometer.