Abstract
In general, injection of an overloaded amount of a sample into a separatory column gives rise to a tailing peak for an eluted component of short retention time, whereas a leading asymmetric peak for the one of long retention time. Induction of tailing peak has been explained to be due to the increase in the flow velocity of carrier gas at high concentration zone of the component. In the present study, it is assumed for the leading peak that leading is caused by that increased part of liquid phase by absorbing the sample vapour also acts as liquid phase : if these increased parts of liquid mixture were eliminated, the distribution ratio of the sample over two phases would be almost independent of the sample concentration. Under these conditions, higher concentration zone will move more slowly than low concentration zone. The validity of the assumption is experimentally verified, using decane-squalane system, by comparing experimental elution curves with calculated ones using plate model, assuming the sample concentration in the gas phase is proportional to the molar fraction of sample in the liquid phase. For tailing peaks, using hexane-squalane system, it is shown that both an increase in flow velocity of carrier gas and an increase in the amount of liquid phase caused by introduction of a sample must be taken into account to explain asymmetry of chromatographic peaks.
