Injection Temperature

What is Mass Discrimination?

Mass discrimination is defined as a unrepresentative sampling from the injector to the column of low and high molecular weight components.

Discrimination - Inlet Temperature

The top chromatogram shows you what happens when the injection port temperature is too low. C22 has not gained enough energy to vaporize during the 1 minute splitless time. Most of the other hydrocarbons are unaffected by the temperature difference, in fact, the areas are the same for C8 to C16 in both chromatograms. But it is clear that 200° C gives much better recoveries for the heavier compounds than 120° C.