通氮蒸馏-自动电位滴定法测定水果制品中二氧化硫残留量  

Determination of Sulfur Dioxide Residue in Fruit Products by Nitrogen Distillation and Automatic Potentiometric Titration

作　　者：冯云[1] 王丹丹 张扬 周玮[1] 张晓强[1] FENG Yun;WANG Dandan;ZHANG Yang;ZHOU Wei;ZHANG Xiaoqiang(Jiangsu Product Quality Testing and Inspection Institute,Nanjing 210007,China)

机构地区：[1]江苏省产品质量监督检验研究院,江苏南京210007

出　　处：《食品安全导刊》2023年第32期53-58,共6页China Food Safety Magazine

基　　金：江苏省市场监督管理局2020年度科技计划项目(KJ207548)。

摘　　要：目的:基于国标酸碱滴定法,建立通氮蒸馏-自动电位滴定法测定水果制品中二氧化硫残留量。方法:称取5 g试样,加入250 mL超纯水,在管路保持通氮速率0.2 L·min^(-1)的情况下,加入10 mL盐酸溶液,立即加热蒸馏管至微沸,蒸馏导管通入50 mL 30 g·L^(-1)碳酸钠溶液中,系统蒸馏微沸1.5 h后停止加热,吸收液中加入10 mL盐酸溶液后,插入复合铂环氧化还原电极,保持搅拌速度30%的搅拌状态,用自动电位滴定仪以碘标准滴定溶液滴定,以电位变化阈值50 mV·min^(-1)作为滴定终点。结果:该方法的回收率在82.0%~98.4%,精密度在0.74%~2.68%。干扰试验结果表明该方法可满足含挥发性酸的样品中二氧化硫残留的检测。在置信水平95%的区间范围内,国标酸碱滴定法和本试验方法同时对两种市售水果制品进行二氧化硫残留量的测定,结果无显著性差异。结论:该方法准确度高、自动化程度高、相对安全,可满足日常水果制品中二氧化硫残留的检测需求。Objective:To establish a method for the determination of sulfur dioxide residue in fruit products by nitrogen distillation and automatic potentiometric titration based on national standard acid-base titration.Method:Weigh the 5 g sample,add 250 mL ultra-pure water,add 10 mL hydrochloric acid solution under the condition that the nitrogenflow rate of the pipeline is 0.2 L·min^(-1),immediately heat the distillation tube to a small boiling,-1 and the distillation tube is passed into 50 mL 30 g·L sodium carbonate solution,and the heating is stopped after 1.5 h of system distillation and small boiling time.After adding 10 mL hydrochloric acid solution into the absorption solution,the composite platinum epoxidation reduction electrode was inserted,and the stirring rate was maintained at 30%.The automatic potentiometric titrator was used to titrate with iodine standard titration solution,and the-1 potential change threshold of 50 mV·min was used as the titration end point.Result:The recovery of the method was 82.0%~98.4%,and the precision was 0.74%~2.68%.Interference test results show that the method can satisfy the determination of sulfur dioxide residues in samples containing volatile acids.Within the range of 95%confidence level,there was no significant difference in the results of sulfur dioxide residue determination of 6 kinds of commercial fruit products by national standard acid-base titration method and this test method.Conclusion:The method has high accuracy,high degree of automation and relative safety,and can meet the requirement of detecting sulfur dioxide residues in daily fruit products.

关 键 词：通氮蒸馏 自动电位滴定 碳酸钠吸收 二氧化硫残留 水果制品 

分 类 号：TS255.7[轻工技术与工程—农产品加工及贮藏工程] O655.2[轻工技术与工程—食品科学与工程]