Optimization and validation of a method for the analysis of target compounds migrating from organic materials used in contact with water intended for human consumption by SPME-GC-TOFMS

Mbenju, John Ekaney

http://hdl.handle.net/10400.1/2887

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Authors

Mbenju, John Ekaney

Advisor(s)

Cardoso, Vitor Vale

Cavaco, Isabel Maria Palma Antunes

Abstract(s)

The leaching of toxic organic substances from polymeric materials in distribution systems into drinking water intended for human consumption has led to an urgent need for the continuous development of new analytical methods for their monitoring and evaluation so that high consumer confidence could be established. An analytical method is developed and validated based on the combination of SPME and GC/TOFMS for the determination of seven target compounds: n-butylacetate, m-xylene, p-xylene, 1,3-dichloroacetone, styrene, o-xylene, cyclohexanone. The chromatographic conditions are optimized so that the analysis is performed in the shortest possible time and a specific mass ion for each compound is targeted in the TOF mass spectrum for quantification. Three SPME adsorption parameters: mode of extraction, extraction temperature and time are optimized for five fibers to attain the best selectivity and sensitivity for each target compound and based on the highest extraction efficiency, the best fiber and its optimized conditions are used for the validation process. The LOD and LOQ were lower than the lowest concentrations used in the calibration curves and the determination coefficient (r2) ranged from 0.995-0.999 within the tested working ranges for all target compounds. The coefficient of variation for repeatability studies was less than 25% for all compounds but it exceeded 25% for some compounds during intermediate precision studies. Recovery studies in both tap and surface water showed that matrix effects play a significant role in the extraction of target compounds from water.