ABSTRACT
The quantitative determination of drugs and their metabolites in biological matrices (bioanalysis) includes a number of steps from sample collection to the final report of the results. The intermediate steps typically include sample storage, sample preparation, separation, identification and quantification of analyte(s). Sample preparation prior to the chromatographic separation has three principal objectives: the dissolution of the analyte in a suitable solvent, removal of as many interfering compounds as possible and pre-concentration of the analyte. A number of techniques such as protein precipitation, liquid–liquid extraction and solid phase extraction (SPE) are routinely used.
