紫外分光光度法检测小麦粉改良剂中三聚硫氰酸三钠盐

Determination of Trisodium Thiocyanate in Wheat Flour Improver by Ultraviolet Spectrophotometry

三聚硫氰酸三钠盐(TMT-Na)是小麦粉及改良剂中非法添加物。采用紫外分光光度法测定小麦粉改良剂中三聚硫氰酸三钠盐含量。通过检测小麦粉样品的吸光度与硫酸铜沉淀TMT-Na后的吸光度差值,计算小麦粉改良剂中实际TMT-Na浓度。结果显示, TMT-Na标准曲线在1~40μg/mL范围内线性良好,线性相关系数R2=0.999 4。方法的检出限为0.2 g/kg,加标回收率在43.3%~84.0%之间,相对标准偏差(SRSD)在2.2%~8.7%之间。该方法操作简单,成本低,检测速度快,适用于大样本的筛查和面粉、添加剂等工厂对原料和产品的自检。

Trisodium thiocyanate(TMT-Na) was used to prepare a compound flour treatment agent and to be added to flour.The content of trisodium thiocyanate in wheat flour improver was determined by ultraviolet spectrophotometry. The actual TMT-Na content in the wheat flour improver was calculated by detecting the difference between the absorbance of the wheat flour sample and the absorbance after copper sulfate precipitation of TMT-Na. The results showed that the TMT-Na aqueous solution had a good linearity in the range of 1-40 μg/mL, and the linear correlation coefficient R2 was 0.999 4. The detection limit of this method was 0.2 g/kg. The recovery rate of standard addition was between 43.3% and 84.0%. The relative standard deviation(SRSD) was between 2.2% and 8.7%. The method was simple in operation, low in cost, and fast in detection speed, and was suitable for screening large samples and self-inspection of raw materials and products in factories such as flour mills and additive factories.