Abstract
A new large volume injection method (Dynamic Retention Gap Method: DRG ) for capillary gas chromatography was developed.
The retention gap consisted of a fused silica tube (2m×0.53mm i.d.) and the pre-column (0.5m×0. 53mm i.d.×0.5μm) was connected with the capillary column by a T-shape connector. A large volume of sample solution (100μl) vaporized in the injection port was rapidly introduced to the retention gap under large flow rate of carrier gas (20ml/min) . After the solvent was purged through the T-shape connector, purge vent was closed and the sample was introduced to the capirally column.
High linearity between injection volume and peak area of pesticide was observed with an in-jection volume of 1 to 100μl in the DRG method.
In the splitless method, some pesticides (DEP, captan, pyridafention, etc.) were decomposed in the injection port by heat. But in the DRG method, those pesticides were able to be analysed with little thermal decomposition, because the pesticide was rapidly introduced to the retention gap from the injection port under large flow rate of carrier gas.
In the GC/MS analysis, the residual water in the sample solution caused a lowering of the sensitivity. In the DRG method, the water was almost purged with solvent, then the contamination of the detector was less than the splitless method.
