蒸馏滴定法测定食品中二氧化硫的方法比较

Comparison of Methods for determining Sulfur Dioxide in Food by Distillation Titration

采用充氮蒸馏-酸碱滴定法与凯氏定氮仪水蒸气蒸馏-碘量法分别测定干香菇、干桂圆和葡萄酒中的二氧化硫含量,并进行方法学比较。结果表明,2种方法测干桂圆和葡萄酒的回收率、精密度和准确度均符合标准要求,无显著性差异。凯氏定氮仪水蒸气蒸馏-碘量法测得干香菇在50 mg·kg^(-1)、200 mg·kg^(-1)加标水平下的回收率分别为176.0%、134.0%,不符合标准要求,因此不适用于香菇中二氧化硫的检测。与凯氏定氮仪水蒸气蒸馏-碘量法相比,充氮蒸馏-酸碱滴定法应用范围更广、准确度更高,但操作复杂,耗时长。

Nitrogen-filled distillation-acid-base titration and Kjeldahl nitrogen determination instrument water vapor distillation-iodometry were used to determine the sulfur dioxide content in dried shiitake mushrooms,dried longan and wine,respectively,and the methodologies were compared.The results showed that the recoveries,precision and accuracy of the two methods for measuring dried longan and wine met the standard requirements,and there was no significant difference.The recoveries of dried shiitake mushrooms at the spiked levels of 50 mg·kg^(-1) and 200 mg·kg^(-1) by the Kjeldahl nitrogen determination instrument water vapor distillation-iodometry were 176.0%and 134.0%,respectively,which were not in accordance with the standard requirements,and therefore not suitable for the detection of sulfur dioxide in shiitake mushrooms.Compared with the Kjeldahl nitrogen determination instrument water vapor distillation-iodometry,the nitrogenfilled distillation-acid-base titration method has a wider range of applications and higher accuracy,but the operation is complex and time-consuming.