The output of the chromatography column is measured by a chromatograph. There are many different types of chromatographs which are used to observe the solutes which are eluted from a chromatography column. A commonality between these detectors are the graphs that they produce, called a chromatogram, as seen below. Basically, a chromatogram is a plot of the detector response, usually the concentration of the solutes emerging from a column, as a function of elution time or volume.
The chromatogram offers an abundance of information about a separation. For example, the efficiency of a separation is determined by the elution times between peaks; the larger the distance between peaks, the better the separation. Also, the wider the peaks, the poorer the separation. In addition, the relative concentrations of the components can be obtained by the peak area comparisons with industrial standards.