重铬酸钾分光光度法测定平湖糟蛋中乙醇含量

Determination of Ethanol Content in Pinghu Egg Preserved in Rice Wine by Potassium Dichromate Spectrophotometry

通过对平湖糟蛋样品前处理方式以及乙醇测定反应体系的优化,建立了重铬酸钾分光光度法测定平湖糟蛋中乙醇含量的方法。平湖糟蛋样品中的乙醇经蒸馏法充分提取,提取液在5.0mL重铬酸钾溶液(50g/L)和2.5mL硫酸溶液(50∶50,v/v)介质中于100℃水浴反应15min,恢复室温后采用分光光度法在585nm处测定吸光度值。该方法能较好排除基质效应影响,测定结果准确度高,乙醇含量在0.00~250.00g/kg范围内线性关系良好,相关系数大于0.999,加标回收率为96.2%~99.5%,精密度(relative standard deviation,RSD)为0.69%~2.28%。该方法操作简单、准确度高、回收率好,能准确地对糟蛋样品中乙醇进行定量检测。

By optimizing the pretreatment method of Pinghu egg preseved in rice wine and the reaction system of ethanol determination,a method for determination of ethanol in Pinghu egg preserved in rice wine by potassium dichromate spectrophotometry was established.The ethanol in the sample ofPinghu egg preserved in rice win was fully extracted by distillation,and the extract was reacted in a water bath at 100℃for 15 min in 5.0 mL potassium dichromate solution(50 g/L)and 2.5 mL sulfuric acid solution(50∶50,v/v),After returning to room temperature,the absorbance was determined at 585 nm by spectrophotometer.The method can eliminate the influence of matrix effect,and the accuracy of the determination results was high.The method had good linear correlation from 0.00 to 250.00 g/kg with all correlation coefficient above 0.999.The average recoveries were from 96.2%to 99.5%with the relative standard deviation(RSD)from 0.69%to 2.28%.The method is simple to operate,has high accuracy,and good recovery rate,which can be used for quantitative determination of ethanol content in Pinghu egg preserved in rice wine.