顶空固相微萃取-气相色谱法检测白酒中吡嗪类化合物

Detection of pyrazine compounds in Baijiu by HS-SPME-GC

该研究从样品前处理、萃取条件两个方面对顶空固相微萃取．气相色谱法检测白酒中吡嗪类化合物进行优化，得到最佳检测条件为：用高纯水将白酒样稀释至酒精度为10％vol，同时向样品中加入NaCl，并使其质量浓度为0．05g／mL，调节样品体系的pH值为8；在70℃条件下，采用50／30μmDVB／CAR／PDMS固相萃取头萃取50min，汽化室温度250℃的条件下解吸3min。方法学研究表明，在0．05~20mg／L的线性范围内具有良好的线性关系，相关系数R〉0．99，8种吡嗪类物质方法的检出限（S／N=3）为1．37~6．78μg／L，回收率87．6％～105．4％，相对标准偏差为4．61％~6．37％。用该方法对5种酱香型白酒检测，所测样品中吡嗪类物质含量在0～29mg／L，其中1^#酒样中吡嗪类物质的含量最高，达到25．72mg／L。

The conditions of sample pretreatment and extraction of pyrazine compounds in Baijiu were optimized by HS-SPME-GC. The optimum de- tection conditions were as follows： alcohol content in Baijiu simple was diluted to 10%vol by pure water. NaCl was added into the sample and its content was 0.05 g/ml. The pH of sample was adjusted to 8. The Baijiu simple was extracted at 70℃ for 50 min with 50/30 μm DVB/CAR/PDMS solid phase extraction head, and the head was desorbed under 250 ℃ for 3 min. Methodology results showed that there was a good linear relationship in the range of 0.05-20 mg/L, the correlation coefficient R was more than 0.99. The limit of detection （S/N=3） of eight kinds of pyrazine compounds was 1.37-6.78μg/L. The recovery rate was 87.6%-105.4%. The relative standard deviation was 4.61%-6.37%. The pyrazine compounds contents in sample detected by the method were 0-29 mg/L, the pyrazine compounds contents in 1^# Baijiu simple was the highest and was up to 25.72 mg/L.