固相微萃取-气相色谱法测定全麦酒酿中乙醇含量

Determination of ethanol content in sweet fermented whole wheat by solid phase microextraction-gas chromatography

中文关键词:  乙醇  顶空固相微萃取  气相色谱法  全麦酒酿

英文关键词:ethanol  headspace solid phase microextraction  gas chromatography  sweet fermented whole wheat

中文摘要:

      目的 建立顶空固相微萃取-气相色谱法测定全麦酒酿中乙醇含量。方法 在10 mL顶空瓶中加入0.1 g经粉碎或者捣碎的样品和5 mL超纯水, 加入氯化钠使其质量分数为40%, 于磁力搅拌下预平衡5 min, 插入羟基硅油/二乙烯基苯萃取头在50 ℃萃取10 min, 拔出萃取头进入气相色谱仪分析。结果 乙醇在100~200000 μg/g范围内呈现很好的线性关系, 线性相关系数r2为0.999; 方法的检测限为11.92 μg/g, 在200、2000、20000 μg/g 3个加标水平上的回收率均在96.51%~103.48%之间, 相对标准偏差小于8.91%。结论 该方法操作简便快速, 样品用量少, 灵敏度高, 结果准确, 重现性好, 适合全麦酒酿等多种酒酿中乙醇含量的测定。

英文摘要:

      Objective To establish a method for determination of ethanol content in sweet fermented whole wheat by headspace solid phase microextraction-gas chromatography (HS-SPME-GC). Methods A portion of 0.1 g smashed or mashed sample was diluted with 5 mL of ultrapure water in a 10 mL headspace vial, and then sodium chloride was added to get a concentration of 40% (W:V). The mixture was incubated at 50 ℃ for 5 min with magnetic stirring. A hydroxy-terminated silicone oil/divinyl benzene fiber was inserted and kept extraction for 10 min at 50 ℃. After extraction, the fiber was transferred to the GC injection port for desorption. Results Ethanol was linear in the range of 100~200000 μg/g with correlation coefficient (r2) of 0.999. The limit of detection was 11.92 μg/g. The recoveries of ethanol were 96.51%~103.48% when spiked at levels of 200, 2000 and 20000 μg/g with the relative standard deviations less than 8.91%. Conclusion The proposed method has the advantages such as simple operation, rapid determination, less sample consumption, high sensitivity, good accuracy and repeatability, which is suitable for determination of ethanol in many kinds of sweet fermented grains.