Determination of six earthy-m/usty odorous compounds in drinking water by headspace solid-phase microextraction coupled with gas chromatography-mass spectroscopy

A new method for the determination of earthy-musty odorous compounds,2-methylisoborneol(MIB),2-isobutyl-3-methoxy pyrazine(IBMP),2-isopropyl-3-methoxy pyrazine(IPMP),2,4,6-trichloroanisole(2,4,6-TCA),2,3,6-trichloroanisole(2,3,6-TCA) and geosmin(GSM) in drinking water by headspace solid-phase microextraction(HS-SPME) combined with gas chromatography-mass spectrometry(GC-MS) was described.The conditions for the analysis of earth-musty odorous compounds were optimized by investigating the type of extraction fiber,desorption time,NaCl concentration,solution pH,headspace temperature,stirring speed,headspace time and GC-MS conditions.The DVB/Carboxen/PDMS coating extraction fiber was selected for HS-SPME.The pH of the sample solution was adjusted to 6.0 by 0.10 mol/L sodium hydroxide solution.Twenty microliter of sample solution with 0.30 g/mL NaCl was equilibrated at 70 ℃ for 25 min.The extraction fiber was injected into GC-MS at 250 ℃ for 4 min.The earthy-musty odorous compounds were then qualified by selected ion monitoring mode.The earth-musty odorous compounds showed good correlation coefficient(R0.986) in the range of 0.25~100 ng/L.The limits of detection were lower than 0.1 ng/L.The method was successfully applied to analysis of earthy and musty odors in real drinking water samples.The relative standard deviations were 3.0%~6.6%(n=6) and the recoveries of the spiked samples were 93.0%~106.6%.The new method was simple,convenient,sensitive,and accurate and was suitable for the determination of earthy-musty odorous compounds in drinking water.