基于离子色谱法测定乳及乳制品中亚硝酸盐含量

Determination of Nitrite in Milk and Dairy Products by Ion Chromatography

建立离子色谱法测定乳及乳制品中亚硝酸盐含量。样品以乙腈为蛋白沉淀剂,3.6 mmol/L Na_(2)CO_(3)为淋洗液,流速为0.7 mL/min,经Metrosep A Suup7-250/4.0色谱柱分离,电导检测器分析,外标法定量。结果表明,亚硝酸盐出峰时间14.4 min,在0.01~2.0μg/mL质量浓度内线性关系良好,检出限为0.02~0.04 mg/kg,定量限为0.04~0.10 mg/kg,方法的平均回收率为85.4%~101.3%,相对标准偏差为1.5%~7.1%(n=6)。试验方法简单高效、重复性好、准确度高,可用于乳与乳制品中亚硝酸盐含量的快速定量分析。

A method for the determination of nitrite in milk and dairy products by ion chromatography was established.The protein in the sample was precipitated by acetonitrile.The eluent was composed of 3.6 mmol/L Na_(2)CO_(3),and the flow rate was 0.7 mL/min.The analysis was performed on Metrosep A Suup7-250/4.0 separation column,and the conductivity detector was used for detection.The results showed that the peak time of nitrite was 14.4 min.The standard calibration curve was linear for nitrite in the concentration range of 0.01-2.0μg/mL,the limit of detections were 0.02-0.04 mg/kg,and the limit of quantifications were 0.04-0.1 mg/kg.The recoveries of nitrite from samples spiked at three different concentrations were within 85.4% to 101.3%,and the relative standard deviation was within 1.5% to 7.1%(n=6).This method was simple,efficient,reproducible and accurate.It could be used for rapid quantitative analysis of nitrite content in milk and dairy products.