Pharmaceuticals and personal care products (PPCPs) have recently emerged as a significant new class of organic micro-contaminants. Of recent years a number of reports detailing the presence of PPCPs in a variety of environmental matrices and compartments have been published in the peer-reviewed literature. However, in Ireland very little research has been conducted to determine the level of environmental contamination due to the presence of drug residues. The primary focus of this research is to develop suitably sensitive analytical methods for the determination of residual PPCP contamination based upon solid phase extraction (SPE) and liquid chromatography mass spectrometry (LC-MS). Monolithic silica based stationary phases were used for the development of high performance liquid phase separations of common pharmaceuticals, the antifouling and anti-dandruff agent zinc pyrithione and a range of illicit drugs and abused pharmaceuticals. As a pre-requisite to all the developed methods, a SPE sample enrichment procedure was also developed focusing upon either off-line formats using modern hydrophilic lipophilic balanced polymeric phases or the use of column switching, whereby short reversed-phase monolithic micro-columns were applied as suitable traps for on-line preconcentration. Method performance data for all the developed methods were also determined and analytical detection limits were found to lie in the ngL-1 range. The developed methods were applied for the determination of the selected analytes in environmental aquatic samples.