Identification of dissolved organic species in non-drinking tap water by solid-phase extraction and gas chromatography–mass spectrometry

A method is presented for qualitative identification of dissolved volatile organic compounds (VOCs) in non-drinking tap water samples based on applications of both solid-phase extraction (SPE) and gas chromatography–mass spectrometric (GC–MS) techniques. Water samples were collected and passed over a micro-column packed with acid treated active silica gel phase (pH = 2.6) for adsorption of dissolved organic species under this pH-condition. Silica-bound-organics were then divided into equal portions followed by suspension into organic solvents of different polarities such as methanol, ethanol, butan-1-ol, ethyl acetate, diethyl ether and chloroform. These suspensions were then automatically shaken for 1 h at room temperature. The organic extracts were subjected to GC–MS analysis under temperature programming conditions. The mass spectrum of each eluted chromatographic peak was library searched or manually interpreted to identify the correct name and structure. Blank solvent and silica samples were also subjected to the same GC–MS analysis for comparison.