A calibration curve is a graphical display of the functional relationship between the expected value of the observed signal to the analyte amount.

In analytical chemistry, a calibration curve is a standard method for determining the concentration of any given compound or element. The experimenter will create a series of standards across the range of concentrations that the analytical technique can determine. They must take care that these concentrations are in the working range of the technique (instrumentation) they are using. These standards will have a precisely known concentration of the element or compound under study. Analyzing each of these standards using the chosen technique will produce a series of readings. By plotting these points (reading vs concentration) on a graph, it is possible to plot a line of reading vs concentration across the analytical range of that technique. Thus, when an unknown sample is run and a reading obtained, the experimenter can simply refer to the graph to obtain the concentration.

Applications

• Analysis of concentration
• Verifying the proper functioning of a sensor device such as an ion-specific electrode
• Determining the basic effects of a control treatment (such as a dose-survival curve in clonogenic assay).