Determination of Odorants of Geosmin, 2-Methylisoborneol and β-Ionone in Source Water of Taihu Lake by Gas Chromatography-Mass Spectrometry after Headspace-Solid Phase Microextraction

The water sample was passed through a 0.45 μm filter membrane, and an aliquot (10 mL) of the filtrate was mixed with 2.5 g of sodium chloride that had been treated at 450℃ for 2 h. Targets in the sample were extracted by Divinylbenzene/Carboxen/Polydimethylsiloxane (DVB/CAR/PDMS) solid microextraction fiber head at 65℃ for 30 min with rotating speed of 500 r·min^-1, and thermally desorbed at 250℃ for 3 min. The obtained gas was introduced into the gas chromatography-mass spectrometer. Separation was performed on HP-5MS chromatographic capillary column with temperature program, and detection for geosmin, 2-methylisoborneol and β-ionone was performed with mass spectrometer equipped with an electron impact ion (EI) source. It was shown that linear relationships between values of the mass concentration and the corresponding peak area were kept in the range of 2.0-200 ng·L^-1 (for geosmin and 2-methylisoborneol) and 1.0-100 ng·L^-1 (for β-ionone), with detection limits (3.36s) of 1.38, 1.12, 0.78 ng·L^-1, respectively. Test for the spiked recovery was carried out on pure water and source water of Taihu lake at the 3 concentration levels, the detected amounts of the 3 odorants in the source water were 1.78, 3.07, 3.81 ng·L^-1, and the recovery was found in the range of 92.3%-111%, with RSDs (n=6) of the determined values in the range of 0.98%-13%, indicating that the proposed method was suitable for the determination of odorants in source water.