Analyzing time varying flow composition using multiple input chromatography

The chromatography of samples whose composition varies with time can be difficult if the time it takes for the sample composition to change is less than the separation time of the sample components. This paper deals with the multiple input chromatography approach, in which multiple injections are performed in such a way that the interval between these injections is one to three orders of magnitude less than the separation time of the sample components. The method does not require extensive hardware modifications of the chromatographic apparatus, but is computationally intensive. Using specifically designed input sequences of the sample, a dramatic increase of the time resolution was achieved. Examples of the monitoring of gases evolving from volcano rock soils and polymers during the heating, from 100 °C to 600 °C, by linear temperature programming are presented.