顶空固相微萃取-气相色谱-质谱法测定大曲中的土臭素

Determination of geosmin in Daqu by headspace solid- phase microextraction coupled with gas chromatography- mass spectrometry

土臭素（geosmin,GSM）是引起白酒土霉味的一种主要化合物,是在大曲制造过程中由微生物产生的。本文建立了一种简便、快速的顶空固相微萃取气相色谱质谱法（HS-SPME-GC-MS）测定大曲中GSM。大曲样品采用乙醇水溶液进行提取,蒸馏后经HS-SPME处理,GC-MS进行分析,外标法定量。在100~8000ng/kg的质量浓度范围内,GSM有较好的线性关系,相关系数（r）大于0.99。通过对大曲空白样品进行加标回收率实验和精密度实验考察方法的可行性。结果表明GSM的回收率为89.19%~98.49%,相对标准偏差介于2.15%与3.06%之间。GSM的检出限为42.6ng/kg,定量限为140.6ng/kg。本方法适用于大曲中GSM的检测。

Geosmin（GSM）, produced by microorganism in Daqu, is the important cause of earthy-mouldy off- flavor in Chinese liquor.A simple and fast method based on headspace solid-phase microextraction（HS-SPME） coupled with gas chromatography-mass spectrometry（GC-MS）was established for the determination of GSM in Daqu. The analytes were extracted by atmospheric distillation with ethanol solution, and then extracted by HS-SPME using 75 μm CAR/PDMS fiber.After concentrating,the sample was analyzed by GC-MS and quantified by the external standard method.The linear ranges were from 100ng/kg to 8000ng/kg for GSM, the correlation coefficient（r） of the calibration curves was 0.999.The recoveries and the relative standard deviations （RSDs）of GSM in Daqu were investigated.The recoveries ranged from 89.19% to 98.49% with the RSDs between 2.15% and 3.06% （n = 5 ）.The limit of detection（LOD） was 42.6ng/kg, and the limit of quantification（LOQ） was 140.6ng/kg.The method is suitable to the determination of GSM in Daqu.