INCREASED ON-COLUMN INJECTION TEMPERATURE FOR GAS-CHROMATOGRAPHY

A way of controlling the maximum allowable oven temperature during on- column injection by the column pressure drop is suggested. An arrangem ent using a restriction at the column outlet for adjustment of the col umn inlet pressure while maintaining the same column flow has been stu died. Compared to non-restricted flow, substantially increased maximum oven temperatures were obtained during on-column injection. Injection s at elevated temperatures resulted in an increased speed of analysis and decreased solute adsorption on the surface of the contaminated ret ention gap. The method is generally applicable to analysis of high boi ling mixtures. In particular, with GC-AED, such an arrangement yields a higher sensitivity due to an increased solute interaction with the e xcitation plasma.