Bioanalysis is a sub-discipline of analytical chemistry covering the quantitative measurement of xenobiotics and biotics in biological systems.Many scientific endeavors are dependent upon accurate quantification of drugs and endogenous substances in biological samples; the focus of bioanalysis in the pharmaceutical industry is to provide a quantitative measure of the active drug and its metabolites for the purpose of pharmacokinetics, toxicokinetics, bioequivalence and exposure–response. Bioanalysis also applies to drugs used for illicit purposes, forensic investigations, anti-doping testing in sports, and environmental concerns.