气相色谱质谱联用法测定封窖泥中的两种土霉味物质

土臭素（GSM）和二甲基异茨醇（2-MIB）是引起白酒土霉味的主要物质。该研究建立了顶空固相微萃取（HS-SPME）结合气相色谱-质谱联用（GC-MS）法测定封窖泥中GSM和2-MIB。该实验对比常压蒸馏萃取和超声波提取对封窖泥中GSM和2-MIB的提取效果，优化顶空固相微萃取（HS-SPME）条件，并对HS-SPME和直接进样两种模式检测结果进行比较。结果表明，超声波提取的最佳条件为：10 m L体积分数50%的乙醇提取两次；HS-SPME最佳萃取条件为：采用65μm PDMS/DVB萃取头，萃取温度50℃，NaCl添加量0.3 g/m L，萃取时间50 min，体积分数5%乙醇提取两次。HS-SPME和直接进样两种进样模式检测结果相对标准偏差（RSD）在3.9%～12.9%之间，相关系数（R2）均≥0.997，加标回收率均在78.47%～110.24%。该方法操作简便高效，精密度、准确度高，适用于封窖泥中GSM和2-MIB的检测。

Determination of two musty-smelling compounds in pit-sealing mud by GC-MS

Geosmin (GSM) and 2-methylisoborneol (2-MIB) are the main substances causing musty smell of Baijiu. In this study, headspace solid-phase microextraction (HS-SPME) combined with GC-MS was established for the determination of GSM and 2-MIB in pit-sealing mud. The extraction effects of atmospheric distillation extraction and ultrasonic extraction on GSM and 2-MIB in pit-sealing mud were compared in this experiment, HS-SPME conditions were optimized, and the determination results of two modes of HS-SPME and direct injection were compared. The results showed that the optimal conditions for ultrasonic extraction were as follows: extraction twice with 10 ml of volume fraction 50% ethanol. The optimal extraction conditions for HS-SPME were as follows: 65 μm PDMS/DVB extraction head, extraction temperature 50 ℃, NaCl addition 0.3 g/ml, time 50 min, and extraction twice with volume fraction 50% ethanol. The relative standard deviation (RSD) of the detection results of the two injection modes of HS-SPME and direct injection were 3.9%-12.9%, the correlation coefficient (R2)≥0.997, and the standard recovery rates were 78.47%-110.24%. The method was simple and efficient with high precision and accuracy, and was suitable for the detection of GSM and 2-MIB in pit-sealing mud.