改良碘量法测定葡萄酒中游离二氧化硫

Determination of Free Sulfur Dioxide in Wine by Improved Iodimetric Method

目的引入葡萄酒样品的前处理方法,建立新的碘量法测定葡萄酒中游离二氧化硫。方法在一定温度和酸性条件下,通入空气,样品中的游离二氧化硫被甲醛吸收液吸收后,加氢氧化钠释放出二氧化硫,用碘标准溶液滴定。结果改良碘量法测定葡萄酒中游离二氧化硫,其测定结果回收率为96.1%、精密度1.23%,灵敏度优于国标法。结论改良碘量法是样品经过前处理,避免了国标氧化法、直接碘量法由于样品中有干扰物质对结果产生的影响,使测定结果更准确。

Objective Study the pretreatment method of wine samples and establish a new iodometric method for the determination of free sulfur dioxide in wine. Methods Under certain temperature and acidic conditions,after the air was injected,the free sulfur dioxide in the sample was absorbed by the formaldehyde. Then the sodium hydroxide was added to release sulfur dioxide,which was Titrated with iodine standard solution. Results The improved iodimetric method for determination of free sulfur dioxide in wine has been established in this paper.The recovery rate is 96. 1%,the precision is 1. 23%,and the sensitivity is better than the national standard method. Conclusion Because of the pretreatment of samples,this method avoids the influence of the result by direct iodine method on the sample due to the exist of the interfering substance,the new Iodometric method studied in this paper,which makes the determination result more accurate.