A graphical representation illustrating the relationship between a known property of a substance and the signal that property produces. This relationship is established by measuring the signals of several samples containing known quantities of the substance. For instance, in spectrophotometry, solutions of a compound at varying concentrations are prepared and their absorbance values are measured. These concentration-absorbance pairs are then plotted, creating a calibration line.
This tool is essential for quantifying the amount of an unknown substance in a sample. Its importance stems from its ability to convert an instrument’s reading into a meaningful concentration value. Historically, creating these involved manual plotting; however, modern instruments often include software that automates the process. The accuracy of any subsequent quantitative analysis relies heavily on the quality of this initial calibration.