乙腈沉淀-离子色谱法测定婴幼儿米粉中硝酸盐和亚硝酸盐

Determination of nitrate and nitrite in infant rice flour by acetonitrile precipitation-ion chromatography

目的建立乙腈沉淀-离子色谱法检测婴幼儿米粉中硝酸盐和亚硝酸的分析方法。方法样品经乙腈:水(5:5,V:V)溶液沉淀蛋白后,在提取温度35℃,超声提取30 min的条件下,过0.22μm滤膜净化。采用KOH水溶液作为流动相进行梯度洗脱,离子色谱检测硝酸盐与亚硝酸盐。结果乙腈沉淀法比较适合婴幼儿米粉中硝酸盐和亚硝酸的提取净化。在提取试剂乙腈:水(5:5,V:V),提取温度35℃,提取时间30 min条件下,米粉中硝酸盐和亚硝酸盐的提取效果最好,回收率均在92.8%~96.8%之间。结论该方法操作简便、提取速度快、检出限低,适用于婴幼儿米粉中硝酸盐和亚硝酸盐的检测。

Objective To establish a method for detecting nitrate and nitrite in infant rice flour by acetonitrile precipitation-ion chromatography.Methods The protein was precipitated from the sample in acetonitrile:water(5:5,V:V)solution,and then purified through a 0.22μm filter membrane under the conditions of extraction temperature of 35℃and ultrasonic extraction for 30 min.Gradient elution using KOH aqueous solution as the mobile phase was performed,and nitrate and nitrite were detected by ion chromatography.Results Acetonitrile precipitation method was more suitable for the extraction and purification of nitrate and nitrite in infant rice flour.Under the conditions of extraction reagent acetonitrile:water(5:5,V:V),extraction temperature 35℃,and extraction time 30 min,the extraction effect of nitrate and nitrite in rice flour was the best,and the recovery rates were 92.8%-96.8%.Conclusion This method is easy to operate,fast to extract,low detection limit,and it is suitable for the detection of nitrate and nitrite in infant rice flour.