Mass Chromatogram - Extracted Ion Chromatogram (XIC)

Extracted Ion Chromatogram (XIC)

In an extracted ion chromatogram (XIC or EIC), also called a reconstructed ion chromatogram (RIC), one or more m/z values representing one or more analytes of interest are recovered ('extracted') from the entire data set for a chromatographic run. The total intensity or base peak intensity within a mass tolerance window around a particular analyte's mass-to-charge ratio is plotted at every point in the analysis. The size of the mass tolerance window typically depends on the mass accuracy and mass resolution of the instrument collecting the data. This is useful for re-examining data to detect previously-unsuspected analytes, to highlight potential isomers, resolve suspected co-eluting substances, or to provide clean chromatograms of compounds of interest. Extracted-ion chromatograms are created via a data-mining or data-analysis process; selected-ion chromatograms, discussed below, arise from a completely different type of experiment, i.e., one in which data is collected only for specific m/z values representing compounds or compound types of interest.