ABSTRACT
This chapter describes the two most popular chromatographic techniques: liquid chromatography (LC) and gas chromatography (GC). It discusses the gas chromatographic process and recent developments pertinent to Therapeutic drug monitoring (TDM) and toxicology. Radioactivity detectors are not used for TDM and toxicology. However, for pharmacokinetic and pharmacological studies, they are quite valuable. Enzyme-multiplied immunoassay techniques (EMIT) has been the most widely used nonradioactive immunoassay for TDM and toxicology. Drug analysis may be performed by a wide spectrum of techniques. The LC design since its inception has followed two approaches, modular and cabinet. Carrier gas is used for transport, but does not directly affect the partitioning procedure, as in the case of the mobile phase in LC. Compared to LC, however, GC drug assays always involve lengthy sample preparation /extraction /derivatization procedures. Immunoassays, such as EMIT and Fluorescence Polarization Immunoassay, have become the dominant and choice methods, as reflected by the survey results, primarily due to ease, efficiency, and precision.
