Calibration, operation that, under specified conditions, in a first step, establishes a relation between the quantity values with measurement uncertainties provided by measurement standards and corresponding indications with associated measurement uncertainties and, in a second step, uses this information to establish a relation for obtaining a measurement result from an indication.
Calibration in chemical analysis is frequently associated with calibrating a measuring instrument or measuring system. Typical features of these are:
they contain chromatographic and/or spectrometric equipment;
they need frequent (daily, weekly, monthly) calibration;
the indication, i.e. the signal from the instrument or system, corresponds to a quantity other than that intended to be measured, e.g. an electric charge or potential, rather than amount-ofsubstance concentration or mass fraction.
The VIM 3 definition is divided into two parts, Figure 2 illustrates the the first part as a calibration diagram.
ref: Terminology in Analytica Measurement Introduction to VIM 3
