Pressure and flow changes in vaporizing GC injectors during injections and their impact on split ratio and discrimination of sample components

The effect of pressure changes in the vaporizing GC injectors on the split ratio is investigated. It is shown that the true split ratio depends on a number of parameters and may strongly differ from the split ratio expected from the flows set before injection. Quantitation with split injection based on external standards has to be carried out very carefully (or should be replaced by the method with internal standard). The split ratio may strongly change during the splitting of the sample. There are a number of mechanisms causing some sample components to be retarded and hence to be split by a different ratio. The split injector is a device which still requires further development.