Determination of Geosmin and 2-Methylisoborneol in Water by Headspace Liquid-Phase Microextraction Coupled with Gas Chromatography-Mass Spectrometry

Abstract

Geosmin (GSM) and 2-methylisoborneol (MIB) were extracted from water samples, adsorbed in organic solvent microdrop by headspace liquid-phase microextraction (HS-LPME), and were analyzed by gas chromatography-mass spectrometry (GC-MS). Influence factors such as the extraction solvent types, headspace and microdrop volumes, stirring rate, equilibrium and extraction time, and ionic strength for HS-LPME efficiency were thoroughly evaluated. Under optimized extraction and detection conditions, the calibration curves of GSM and MIB were linear in the range of 5–1000 ng/L. The detection limits of GSM and MIB were 1.1 and 1.0 ng/L, respectively. Average recoveries of 95.45–113.7% (n = 5) were obtained and method precisions were also satisfactory. Trace levels of the off-flavor compounds at ng/L in tap water and raw water were successfully quantified.

Keywords:

• Gas chromatography-mass spectrometry
• Geosmin
• Headspace liquid-phase microextraction
• 2-Methylisoborneol
• Single-drop microextraction
• Water samples

Acknowledgments

This work was supported by the Department of Science and Technology of Shandong Province of China (2008GG20005005), the National Natural Science Foundation of China (20975089), Water Pollution Control and Treatment S&T Major Project of China (Grant No. 2009ZX07422-006), and the Ministry of Water Resources Public Welfare Specialized Research Foundation of China (200901063), Innovation Projects of the Chinese Academy of Sciences (KZCX2-EW-206, KZCX2-YW-Q07-04) and the 100 Talents Program of the Chinese Academy of Sciences.

Notes

^a HS-LPME conditions were the same as those described in Figure 4.

^b #1 Mixed water from Dagu River and Jihongtan Reservoir (1:1, v/v); #2 Laoshan Reservoir water; #3 Effluent water from Xianjiazhai; #4 Yellow River water; #5 Effluent water from Baisha River; #6 Influent water from Qingdao Liuting water Co. Ltd.; and #7 Effluent water from Qingdao Liuting water Co. Ltd.

^c Averaged from five determinations.

^d Not detected.

^a HS-LPME conditions were the same as those described in Figure 4.

^b Effluent water samples treated from Qingdao Liuting Water Co. Ltd.