液液微萃取结合气质联用技术分析高温大曲中风味物质

该研究建立液液微萃取（LLME）结合气相色谱-质谱（GC-MS）联用技术分析高温大曲中风味物质的方法，并优化前处理条件。结果表明，最佳前处理条件为：称取大曲样品15 g；提取溶剂为30 mL体积分数40%乙醇；提取方式为先以转速450 r/min摇床振摇15 min，再经过120 W超声仪超声提取5 min；萃取剂及用量为乙醚2 mL；漩涡振荡时间40 s。在此优化前处理条件下，GC-MS共检出25种风味物质，其中酸类7种、芳香族6种、吡嗪类5种、杂环类2种、醇类2种、以及酚类、酮类和含硫化合物各1种。各风味物质标准曲线的线性关系良好，相关系数R2均≥0.99，精密度试验结果相对标准偏差（RSD）≤7.26%，加标回收率为80.25%～119.26%，方法检出限为0.13～50.17 μg/kg，定量限为0.44～167.22 μg/kg。该方法精密度及准确度良好，可满足大曲风味物质准确定量分析要求。

Analysis of flavor compounds in high-temperature Daqu by liquid-liquid microextraction combined with gas chromatography-mass spectrometry

Flavor compounds in high-temperature Daqu were analyzed by liquid-liquid microextraction (LLME) combined with GC-MS, and the pretrea- tment conditions were optimized. The results showed that the optimum pretreatment conditions were as follows: 15 g Daqu was dissolved in 30 ml ethanol with volume fraction 40%, then shaken on the shaking table at 450 r/min for 15 min and ultrasonic extracted at 120 W for 5 min, the extraction agent and dosage was ether 2 ml, and the vortex oscillation time was 40 s. Based on the optimal pretreatment conditions, a total of 25 flavor compounds were detected, including 7 acids, 6 aromatics, 5 pyrazines, 2 heterocycles, 2 alcohols, 1 phenol, 1 ketone and 1 sulfur compound. The standard curve of flavor compounds in Daqu had good linearity, the correlation coefficient (R2) was all above 0.99, the relative standard deviation (RSD) of precision test result was less than 7.26%, the standard addition recovery rate was 80.25%-119.26%, the detection limit of the method was 0.13-50.17 μg/kg, and the quantification limit was 0.44-167.22 μg/kg. The method had good precision degree and accuracy, and could meet the requirements for accurate quantitative analysis of flavor compounds in Daqu.