Calibration in analytical chemistry refers to the
relation between sample domain and measurement domain (signal domain)
expressed by an analytical function x = fs(Q)
representing a pattern of chemical species Q and their amounts or concentrations
x in a given test sample on the one hand and a measured function
y = f(z) that may be a spectrum, chromatogram,
etc.
Simultaneous multispecies analyses are carried out mainly by spectroscopic
and chromatographic methods in a more or less selective way. For the
determination of n species Qi (i = 1,2
…n), at least n signals must be measured which should be
well separated in the ideal case. In analytical practice, the situation
can be different.