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Chromatograms

Chromatograms represent the signal strength acquired by the HPLC detector vs. time. Before the compound reaches the detector, there is some background noise signal called the baseline. When the compound reaches the detector, this signal starts increasing until a maximum and then decreases until all of the compound has been detected. This maximum corresponds to the peak height. The time from the injection until this peak maximum is the retention time (tR).

From the baseline, the curve contains a defined area under it. This peak area is used to make a calibration based on the fact that the area is proportional to the concentration of the compound. The higher the concentration, the larger the peak area and the higher the peak height.

Graph with y-axis labeled detector response and x-axis labelled time. Sample injection baseline is a flat line just above zero. A red line curves upwards from the baseline at an example time point and peaks then curves downwards towards the baseline. There is an arrow from the baseline to the top of the peak labelled peak height. Another arrow from baseline to half the peak height is labelled height divided by 2. The retention time is the time from the injection point to the time of the peak height.

Figure 1. Example of a chromatogram.

Referred from:

Article
High Performance Liquid Chromatography (HPLC)