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J Chromatogr A

Title:		Full evaporation dynamic headspace and gas chromatography-mass spectrometry for uniform enrichment of odor compounds in aqueous samples
Author(s):		Ochiai N; Sasamoto K; Hoffmann A; Okanoya K;
Address:		"GERSTEL K.K., 1-3-1 Nakane, Meguro-ku, Tokyo 152-0031, Japan. nobuo ochiai@gerstel.co.jp"
Journal Title:		J Chromatogr A
Year:		2012
Volume:		20120409
Issue:
Page Number:		59 - 68
DOI:		10.1016/j.chroma.2012.03.097
ISSN/ISBN:		1873-3778 (Electronic) 0021-9673 (Linking)
Abstract:		"A method for analysis of a wide range of odor compounds in aqueous samples at sub-ng mL(-)(1) to mug mL(-)(1) levels was developed by full evaporation dynamic headspace (FEDHS) and gas chromatography-mass spectrometry (GC-MS). Compared to conventional DHS and headspace solid phase microextraction (HS-SPME), FEDHS provides more uniform enrichment over the entire polarity range for odor compounds in aqueous samples. FEDHS at 80 degrees C using 3 L of purge gas allows complete vaporization of 100 muL of an aqueous sample, and trapping and drying it in an adsorbent packed tube, while providing high recoveries (85-103%) of the 18 model odor compounds (water solubility at 25 degrees C: log0.54-5.65 mg L(-)(1), vapor pressure at 25 degrees C: 0.011-3.2 mm Hg) and leaving most of the low volatile matrix behind. The FEDHS-GC-MS method showed good linearity (r(2)>0.9909) and high sensitivity (limit of detection: 0.21-5.2 ng mL(-)(1)) for the model compounds even with the scan mode in the conventional MS. The feasibility and benefit of the method was demonstrated with analyses of key odor compounds including hydrophilic and less volatile characteristics in beverages (whiskey and green tea). In a single malt whiskey sample, phenolic compounds including vanillin could be determined in the range of 0.92-5.1 mug mL(-)(1) (RSD<7.4%, n=6). For a Japanese green tea sample, 48 compounds including 19 potent odorants were positively identified from only 100 muL of sample. Heat-induced artifact formation for potent odorants was also examined and the proposed method does not affect the additional formation of thermally generated compounds. Eighteen compounds including 12 potent odorants (e.g. coumarin, furaneol, indole, maltol, and pyrazine congeners) were determined in the range of 0.21-110 ng mL(-)(1) (RSD<10%, n=6)"
Keywords:		Alcoholic Beverages Gas Chromatography-Mass Spectrometry/instrumentation/*methods Limit of Detection Odorants/*analysis Reproducibility of Results Tea Volatile Organic Compounds/*analysis;
Notes:		"MedlineOchiai, Nobuo Sasamoto, Kikuo Hoffmann, Andreas Okanoya, Kazunori eng Netherlands 2012/05/01 J Chromatogr A. 2012 Jun 1; 1240:59-68. doi: 10.1016/j.chroma.2012.03.097. Epub 2012 Apr 9"