Among the biological samples, urine is the primarily preferred specimen for drug testing because specimen collection is simple and non-invasive and drugs and their metabolites tend to be present in relatively high concentrations. For the determination of those drugs, gas chromatography (GC), high-performance liquid chromatography (HPLC), and high performance capillary electrophoresis (HPCE) have proved to be very effective. The dominant confirmatory method for the determination of positive samples is GC coupled with mass spectrometry (GC–MS), because it allows for the
possibility of accurate quantification in relatively short analysis times with adequate resolution between structurally close-related components. Reports of the use of this simultaneous determination method for ATS and cannabinoids are a few, because they have dissimilar
chemical properties i.e., it is difficult to apply an identical sample
preparation conditions such as extraction and derivatization
methods for both drugs. The previous reported method [18] also
showed weakness of determining ATS concentration and applied matrix
(nail) was different.