Detection and Measurement of Trihalomethanes in Drinking Water using Solid-Phase Micro-Extraction and Gas Chromatography-Mass Spectrometry(Case Study of Mazandaran Province Cities)

Chlorination for disinfection of drinking water leads to the formation of by-products like trihalomethanes, due to the reaction of chlorine with natural organic compounds like tannic acid, fulvic acid, and humic acid. Due to the carcinogenicity of these compounds, rapid measurement of these compounds in water requires rapid and sensitive analytical methods. In this study, solid-phase microextraction was used as a solvent-free separation and pre-condensation technique to determine four common halomethanes in drinking water using gas chromatography with mass spectroscopy. In this technique, polydimethylsiloxane fiber was used as headspace method for pre-condensation and extraction of the analyte from the aqueous sample. Detection and measurement of the extracted analytes was conducted using thermal desorption in the injection chamber of gas chromatography-mass spectroscopy. Various parameters affecting the efficiency of trihalomethane extraction, including the extraction and desorption temperature, the extraction and desorption time in addition to the amount of salt were investigated and optimized. Under optimal conditions, the concentration factor of detection limit was obtained in the range of 2.1 to 4.4 µg/l and the linear range of 20 to 600 µg/l. Relative standard deviation was obtained to be between 2.5% and 3.1% at the concentration of 30 µg/l trihalomethanes in water. The method was successfully applied to extract and determine trihalomethanes in drinking water in cities of Mazandaran Province.