离子色谱法测定湖南省市售液态乳中硫氰酸盐的含量

Detection of thiocyanate content in liquid milk from the markets in Hunan Province by ion chromatography

目的建立液态乳中硫氰酸盐的离子色谱检测方法，对湖南省内市售液态乳中硫氰酸盐的含量进行测定。方法样品加入乙腈，离心沉淀蛋白，过IC—RP柱净化，用MetrosepASupp4阴离子交换柱在5mmol／LNa2CQ＋5％丙酮淋洗液下分离，电导检测器检测。结果液态乳中硫氰酸盐的检出限为4×10-4mg／L，在0．1～2．0mg／L浓度范围内线性关系良好，相关系数为0．9998，样品加标回收率在91．7％～102％之间，精密度RSD为4．2％。对湖南省内101份市售液态乳中的硫氰酸根进行了检测，检出率为100％，含量范围为2．1～8．9mg／kg。结论该方法的准确度高、重复性好、检出限低，且所需仪器配置简单，适合向基层实验室推广。实验结果为液态乳中硫氰酸盐的本底值调查提供了可参考数据。

Objective To develop an ion chromatography method for determination of thiocyanate content in liquid milk from the markets in Hunan Province. Methods The samples were analyzed by Metrohm 881 ion chromatograph after extraction and purification, thiocyanate was separated by Metrosep A Supp 4 anion analysis column with 5 mmol/L Na2 CO3 and 5 % acetone as eluent, then detected by conductivity detector. Results The results showed that the detection limit of thiocyanate was 4 ×10 4 mg/L, the linear relation was good at the range of 0.1 - 2.0 mg/L, the correlation coefficient was 0. 9998, the recovery was at the range of 91.7% - 102%, and the relative standard deviation （RSD） was 4.2%. We detected thiocyanate content in 101 liquid milk samples from the markets in Hunan Province, the detection rate was 100%, and the range of the content was 2.1 - 8.9 mg/kg. Conclusions The method has high accuracy, good reproducibility and low detection limit; moreover, it only needs simple instrument and is suitable for basic laboratories. The results of this study can provide some references for further re- search on the background value of thiocyanate in liquid milk.