Dry Purge Research Articles

Effect of a dry purge step on the analysis by dynamic headspace - GC-MS of the volatile fraction of a cheese

A dry purge procedure was used to eliminate water during the analysis of the volatile fraction of a water-rich cheese, by dynamic headspace-GC-MS. The impact of the duration of this procedure on chromatographic profile was studied for dura- tions ranging from 0 to 50 minutes. A dry purge duration of 3 minutes sufficed to reduce the water peak area and improve the quality of the chromatographic signal. However, the dry purge procedure induced marked modifications to the chromatographic profile of the cheese throughout the range of component polarities.

Effect of operating parameters in purge-and-trap GC-MS of polar and nonpolar organic compounds

The operating parameters of purge-and-trap sampling significantly affect the sensitivity of the analysis of volatile organic compounds in water samples. The effects of puge volume, sample temperature, sample volume, dry purge volume, desorption temperature, desorption time and cold-trap temperature have been studied for some polar and nonpolar organic volatiles using a purge-and-trap sampler interfaced with a direct coupling to a gas chromatograph-mass spectrometer. It is shown that the sensitivity and in some cases the specificity of the method can be greatly improved through careful optimization.