A study of the influence of the injection duration on the precision of concentration estimation in chromatography Original Research Article

The duration of the injection is one of the parameters influencing the result of a chromatographic analysis. With a longer injection time a bigger amount of the mixture to be analyzed is injected into the column and the detected signal is increasing. The increase of the signal is reached without increasing the flow rate or applying pre-concentration. A longer injection duration results in non-Gaussian peaks and in a bigger overlap of the peaks. However, if the shape of the resulting peaks is known in advance, then the intensity of the peaks and with that the concentration of the components can be determined with a higher precision despite the bigger overlap. A negative side effect of this approach is a longer analysis time. Defining estimation efficiency as the gained precision per analysis time unit and using it as a criterion, an optimal injection duration can be calculated. An optimal injection duration depends on the properties of the column and on the composition of the analyte.