柱后衍生-离子色谱-紫外检测法测定食品中亚硝酸盐含量

Determination of nitrite in food by post-column derivatization-ion chromatography-ultraviolet detection

目的建立柱后衍生-离子色谱-紫外检测法测定食品中亚硝酸盐含量的分析方法。方法样品用水进行超声提取,采用亚铁氰化钾-乙酸锌溶液沉淀后离心过滤,样品溶液中的亚硝酸盐经离子色谱分离后在酸性条件下与对氨基苯磺酸及N-(1-萘基)-乙二胺二盐酸盐偶合生成紫红色染料,紫外检测器在538 nm波长下检测,外标法定量。结果以KOH溶液为流动相,亚硝酸盐在0.001~0.100 mg/L质量浓度范围内线性良好,检出限低至0.05 mg/kg,食品样品中亚硝酸盐的加标回收率在90.4%~109.0%之间,6次重复测量的相对标准偏差均小于10%。结论本方法具有灵敏度高、特异性强、前处理简便等优点,适合于各种类型样品中亚硝酸盐的检测。

Objective To establish an analytical method for the determination of nitrite content in food by post-column derivatization-ion chromatography-ultraviolet detection.Methods The samples were extracted by ultrasonic with water,precipitated with potassium ferrocyanide-zinc acetate solution and filtered by centrifugation,the nitrite in the sample solution was separated by ion chromatography,and derivatizated with p-aminobenzene sulfonic acid and N-(1-naphthyl)-ethylenediamine dihydrochloride under acidic conditions to form a purple dye,and then detected by ultraviolet detector at 538 nm,and quantified by external standard method.Results With KOH solution as the mobile phase,the linearity of nitrite was good in the mass concentration range of 0.001‒0.100 mg/L,and the limits of detection were as low as 0.05 mg/kg,the spiked recoveries of nitrite in food samples were in the range of 90.4%‒109.0%,and the relative standard deviations of the 6 repeated measurements were all less than 10%.Conclusion This method has the advantages of high sensitivity,high specificity and easy pretreatment,and is suitable for the detection of nitrite in various types of samples.