what is a chromatogram

A chromatogram is the visual output of a chromatography run. It is essentially an electronic file or hardcopy containing the information generated during the chromatography run. The chromatogram is a two-dimensional plot with the ordinate axis giving concentration in terms of the detector response, and the abscissa represents the time. Different peaks or patterns on the chromatogram correspond to different components of the separated mixture. The chromatogram can be used to determine the existence and possibly also the concentration of analyte(s) in a sample. The trace on the chromatogram should always be checked, as this will be the first indication if anything has gone wrong with the chromatography. The minimum information shown on a chromatogram depends on the settings used in each laboratory and any regulatory requirements. Chromatograms can be interpreted similarly to graphs that describe position and velocity in physics. In this case, the position corresponds to the compound’s retention time while its speed correlates to the intensity (or concentration) of the compound.