Analysis of earthy and musty odors in water samples by solid-phase microextraction coupled with gas chromatography/ion trap mass spectrometry

A method for the determination of the earthy and musty odors geosmin, 2-methylisoborneol (2-MIB), 2-isobutyl-3-methoxy pyrazine (IBMP), 2-isopropyl-3-methoxy pyrazine (IPMP) and 2,4,6-trichloroanisole (2,4,6-TCA) in water by headspace solid-phase microextraction (HSSPME) combined with gas chromatography-ion trap mass spectrometry (GC-ITMS) is described. Several parameters of the extraction and desorption procedure were studied and optimized (such as types of fibers, extraction temperature, extraction time, desorption temperature, desorption time, ionic strength and elutropic strength and pH of samples). The method shows good linearity over the concentration range 1-500 ng l−1 and gives detection limits of sub-part per trillion levels for all compounds. Good precision (5.9-9.8%) is obtained using IBMP as internal standard. Finally, the method was successfully applied to analyze earthy and musty odors in tap water and lake water.