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  • Optimization and validation of a method for the analysis of volatile organic compounds in water intended for human consumption by SPME-GC-MS
    Publication . Herendi, Lili; Cardoso, Vitor Vale; Cavaco, Isabel
    Volatile organic compounds may occur in water intended for human consumption, mainly as by-products of drinking water treatment, or due to inefficiency of the treatment process. Water is essential to life, therefore efforts should be made to achieve safe drinking-water, including the monitoring of water quality. Therefore, an analytical method was developed, optimized and validated based on the combination of gas chromatography and mass spectrometry using solid-phase-microextraction for sample preparation (SPME-GC-MS). This work, was studying fifteen target organic compounds with the above mentioned equipment: para-xylene, meta-xylene, orto-xylene, methyl-tertiary-butyl-ether, pentachlorobenzene, 1,2–dichloroethane, benzene, epichlorhydrin, 1,2–dichlorobenzene, 1,3–dichlorobenzene, 1,4–dichlorobenzene, 1,2,3–trichlorobenzene, 1,2,4–trichlorobenzene, 1,3,5–trichlorobenzene and ethylbenzene. In order to achieve the best sensitivity and selectivity for each target organic compound, after selecting the optimal fiber for the extraction, some parameters at the sample preparation procedure, such as extraction time, extraction temperature, salt addition effect, and effect of stirring were optimized. The work also involved the optimization of the conditions of the GC-MS system, defining the optimal desorption time and the evaluation of different temperature programs. The method obtained with the previously optimized conditions, was then validated through the study of linearity, accuracy and precision and evaluation of the analytical limits. The determination coefficients (r2) obtained in the linearity studies for the majority of the compounds were above the recommended value of 0.995, except for epichlorhydrin. The LOD and LOQ were quite satisfactory for the majority of compounds, except MTBE and PeCB. The target compounds had recoveries in tap water, surface water and ground water between a range of 65-135%.
    2012Dissertação de mestrado Acesso restrito Ver mais