The chemical data analysis defined by the term "chemometrics" means performing calculations on measurements of chemical data. This can be anything from- calculating pH from a measurement of hydrogen ion activity to computing a Fourier transform interpolation of a spectrum.The science of chemometrics gives spectroscopists many different ways to solve the calibration problem for analysis of spectral data. Some are very simple to understand, while others require a strong background in linear algebra. However, they all have one thing in common: they each solve an individual problem but do not address ALL possible problems

Chemical analysis, which relies on the use of measurements, is divided into two categories depending on the manner in which the assays are performed. Classical analysis, also termed wet chemical analysis, consists of those analytical techniques that use no mechanical or electronic instruments other than a balance. The method usually relies on chemical reactions between the material being analyzed (the analyte) and a reagent that is added to the analyte. Wet techniques often depend on the formation of a product of the chemical reaction that is easily detected and measured. For example, the product could be coloured or could be a solid that precipitates from a solution.

Most chemical analysis falls into the second category, which is instrumental analysis. It involves the use of an instrument, other than a balance, to perform the analysis. A wide assortment of instrumentation is available to the analyst. In some cases, the instrument is used to characterize a chemical reaction between the analyte and an added reagent; in others, it is used to measure a property of the analyte. Instrumental analysis is subdivided into categories on the basis of the type of instrumentation employed