吡嗪类化合物在白云边酒中的变化 Changes of Pyrazines in Baiyunbian Liquor

吡嗪类化合物是白酒中重要的含氮化合物，对白酒的风味有重要的影响。为分析吡嗪类化合物在白云边酒中的变化，建立了间接固相微萃取与气相色谱–质谱(GC-MS)联用技术，采用外标法快速定量检测白云边酒中2-甲基吡嗪、2,5-二甲基吡嗪、2,3,5-三甲基吡嗪、2,3,5,6-四甲基吡嗪的含量。间接固相微萃取：先对酒样预处理，将酒样用H2SO4调节pH值为1，用旋转蒸发仪蒸发浓缩，收集浓缩液用NaOH调节pH值为12。再顶空固相微萃取，取1 ml浓缩液于顶空瓶中，加入NaCl直到浓缩液饱和。40℃保持15 min，并且在相同的温度下萃取20 min。气相色谱–质谱分析结果显示：吡嗪类化合物含量与年份有着密切关系。白云边年份酒中尤其12年~15年是各类吡嗪含量变化的转折点，四种吡嗪总含量随年份增长而递增。 Pyrazines are one of the most important flavors in liquor. To analyze the changes of pyrazines in Baiyunbian liquor, a technique of indirect solid phase microextraction and GC-MS was established. The contents of 2-methylpyrazine, 2,5-dimethylpyrazine, 2,3,5-trimethylpyrazine, 2,3,5,6-tetrame- thylpyrazine in Baiyunbian liquor were detected by external standard method. Indirect solid phase microextraction: First wine was pretreated, the samples were adjusted to pH1 with H2SO4, evaporate and concentrate with a rotary evaporator, then adjusted to pH12 with NaOH. Headspace solid phase microextraction: take 1 ml of concentrate in a headspace bottle and add NaCl until the concentrate is saturated. The temperature is kept at 45˚C for 15 min, and the concentrate was extracted at the same temperature for 20 min. The results show that the content of pyrazines is closely related to the year. 12 - 15 years is the turning point of the change in pyrazine content, the total content of four pyrazines increased with the year.