Pharmaceuticals and personal care products (PPCPs) have emerged in recent years as a new class of chemical and biological pollutants in our environment. In the search for suitably sensitive and specific techniques for detection of these compounds at very low concentrations, liquid chromatography-tandem mass spectrometry (LCMS/ MS) has emerged as the new technique of choice. This work describes methods for screening and quantification of various pharmaceutical and illicit drug residues in solid and liquid environmental and biological matrices. Particular focus was given to efficiency of chosen stationary phase, sample preparation procedures and matrix effects which seriously affect the accuracy of LC-MS/MS measurements. An analytical method was developed for the analysis of a range of illicit drugs in hair samples. The solid phase extraction procedure was optimised by comparison of the extraction efficiency of a range of commercially available cartridges. The method was validated and applied to the detection of cocaine traces in the hair of a recreational drug user. In the area of high performance liquid chromatography (HPLC) the advantages of new monolithic stationary phases over traditional particle packed beds is becoming apparent. In this work, the performance of a half-metre monolithic column was characterised using van Deemter plots. The separation efficiency of the monolith was compared to that of a conventional particulate column with promising results. Investigations into loading capacity and peak capacity of the half-metre monolith also highlighted the suitability of the long monolith for the screening of large numbers of pharmaceutical compounds. The half-metre monolithic column was applied to the analysis of pharmaceuticals and personal care products (PPCPs) in complex environmental and biological samples. The effects of ion suppression on mass spectrometric sensitivity for detection of pharmaceuticals in extracts of both soil and sludge were quantified for the long monolithic column and a particle packed column. The half-metre monolith demonstrated less ion suppression for the majority of analytes. The monolith was then applied to the etermination of PPCPs in urine samples with minimal sample preparation.