Determination of Seven Musty Odor Compounds in Water by Gas Chromatography Mass Spectrometry with Headspace Solid Phase Micro-Extraction

A method for the simultaneous determination of seven musty odor compounds [geosmin (GSM), 2-methylisoborneol (2-MIB), 2-isopropyl-3-methoxypyrazine (IPMP), 2-isobutyl-3-methoxypyrazine (IBMP), 2, 4, 6-chloroanisoles (2, 4, 6-TCA), 2, 3, 6-chloroanisoles (2, 3, 6-TCA) and 2,3, 4-chloroanisoles(2, 3, 4-TCA)) in water by gas chromatography-mass spectrometry (GC-MS) with headspace solid phase micro-extraction (HS/SPME) has been developed. The extraction method was absolutely solvent-free with a divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fiber used for the enrichment of analytes. To obtain the highest sensitivity, the condition parameters of HS/SPME were optimized. The final conditions were as follows: 6 g NaCl, extraction temperature of 90 degrees C, 20 mL sample volume, extraction time of 30 min and desorption time of 5 min. Selected ion monitoring (SIM) mode of GC-MS was used in quantitation. The selected ions for SIM detections were 137 m/z for IPMP, 124 m/z for IBMP, 95 m/z for 2-MIB, 195 m/z for 2,4, 6-TCA, 210 m/z for 2,3,6-TCA, 112 m/z for GSM and 210 m/z for 2,3, 4-TCA. The method had linear response within (1 - 100) ng/L with a correlation coefficient above 0. 997, and the detection limits (S/N=3) were below 1. 0 ng/L. The intra-day (n=6) precision was from 1. 4% to 3. 4% and inter-day precision (m=2, n=6) was from 4. 2% to 6. 9%. The method was successfully applied to analyze environment water sample and the recoveries of seven compounds were in the range of (84. 0% - 105. 0%) at spiked levels of (3-10) ng/L. The present method was compared with other methods in literature for the determination of musty odor compounds in water sample.