Water pollution presents a very critical problem facing industrial and developping countries. The environmental monitoring of the contaminants seems necessary to understand their sources and impacts. Among a wide variety of organic pollutants present in water, polycyclic aromatic hydrocarbons (PAHs) and pesticides are of particular importance as widespread, persistent, and toxic contaminants. They are usually present at trace levels in the acquatic surfaces; therefore their detection and control require selective and sensitive analytical procedures. The Solid-Phase Extraction (SPE) followed by the Gas-Chromatography coupled to Mass Spectrometry (GC-MS) are the most commonly used techniques for their analysis in water. Thesis objectives are focused on the development of new analytical methods for the extraction and analysis of these two families of pollutants present in water. To overcone the contraints of the traditional SPE, a new approach was developed consisting on the introduction of the centrifugation in several steps of the procedure. The new method showed practical environmental and economical advantages in terms of sample preparation time, simplicity, reduction in solvent use, and cost and is particularly suitable for routine applications requiring a high sample throughput. A programmed temeperature vaporizing (PTV) injection method was also optimized and validated in order to improve the detection limits for the GC-MS analysis of PAHs. The evaluation of the quality of different water systems in Lebanon including rainwater, groundwater, drinking water and surface water was accomplished in this study.
