离子色谱-电导检测法测定不同乳制品中硫氰酸盐

建立了离子色谱-电导检测分析不同类型乳制品中硫氰酸盐(SCN-)污染物的方法,重点研究了不同形态样品如固态类(奶粉)、液态类(牛奶)、凝固态类(凝固型酸奶)和半流质态类(炼乳)等乳制品中的硫氰酸盐前处理方法,采用丙酮作为蛋白沉淀剂,有效实现了对各类样品中蛋白质的沉淀和对硫氰酸盐的提取,避免了以往采用乙腈处理样品时容易分层的弊端,方法在0～5.0mg/L浓度范围内具有良好的线性关系,相关系数r为0.9997(n=6),方法检出限(LOD)为0.15～0.5μg/g,方法回收率为95.0%～105.0%,相对标准偏差(RSD)为1.4%～5.6%(n=3)。

Determination of Thiocyanate Contaminant in Different Types of Dairy Products by Ion Chromatography with Conductivity Detection and Sample Pretreatment

A method was developed for analysis of thiocyanate (SCN-) contaminant in different types of dairy products using ion chromatography with conductivity detection.The focus was on the sample pretreatment for analyzing different forms of dairy products including solid state (milk powder), liquid (milk), condensed state(yoghurt) and semi-liquid state (condensed milk). Acetone was used to precipitate protein and results showed that acetone can precipitated all kinds of proteins and extract the thiocyanate (SCN-) contaminant and also avoid the stratification problem occurred when acetonitrile was used as the protein precipitant.Under the optimal conditions, the calibration curve was linear in the range of 0~5.0 mg/L, with the linear correlation coefficient of r=0.9997 (n=6).And for different types of dairy products, the limits of detection (LOD) were in the range of 0.15 μg/g to 0.5 μg/g, the recoveries were between 95.0 % to 105.0%, and the relative standard variations (RSD) were about 1.4% to 5.6% (n=3).