酸碱滴定法测定饼干中二氧化硫含量的不确定度评定  

Evaluation of Uncertainty in Determination of Sulfur Dioxide Content in Biscuits by Acid-Base Titration

作　　者：何金麟 王仍瑞 孙婷 HE Jinlin;WANG Rengrui;SUN Ting(Technical Center of Xiamen Customs,Xiamen 361026,China)

机构地区：[1]厦门海关技术中心,福建厦门361026

出　　处：《食品安全导刊》2023年第27期105-109,共5页China Food Safety Magazine

摘　　要：目的:采用酸碱滴定法测定饼干中的二氧化硫残留量,并对测定结果的不确定度进行分析及评定。方法:试样酸化后在充氨蒸馏条件下释放二氧化硫,用过氧化氢溶液吸收,氢氧化钠标准溶液滴定,根据滴定体积计算二氧化硫含量。通过建立数学模型,分析检测过程引入的不确定来源和数值,计算各影响因素的不确定度分量,最终得出不确定度报告。结果:在95%置信区间下,扩展不确定度为1.2 mg·kg^(-1)。饼干中二氧化硫残留量测定结果可报告为(179.11±1.2)mg·kg^(-1)(k=2,置信区间p=95%)。结论:影响测定结果准确性的主要因素为样品测量重复性和试样称量,应在实验过程中加以重点关注及控制,使检测结果更可靠。Objective:The residual amount of sulfur dioxide in biscuit was determined by acid-base titration,and the uncertainty of the result was analyzed and evaluated.Method:After acidification,the sulfur dioxide was released under the condition of ammonia filled distillation,absorbed by hydrogen peroxide solution,titrated by sodium hydroxide standard solution,and the sulfur dioxide content was calculated according to the titration volume.By establishing a mathematical model,analyzing the source and value of the uncertainty introduced in the detection process,calculating the uncertainty component of each influencing factor,and finally obtaining the uncertainty report.Result:At 95%confidence interval,the extended uncertainty is 1.2 mg·kg^(-1).Determination of sulfur dioxide residue in biscuits can be reported as(179.11±1.2)mg·kg^(-1)(k=2,confidence interval p=95%).Conclusion:The main factors affecting the accuracy of the test result are the repeatability of the sample measurement and the weighing of the sample,which should be paid attention to and controlled during the experiment to make the test result more reliable.

关 键 词：酸碱滴定法 二氧化硫 不确定度 饼干 

分 类 号：O655.2[理学—分析化学] TS213.22[理学—化学]