原子吸收光谱法测定特殊医学配方食品中钾元素分析条件的优化

Optimization of analytical conditions of potassium in special medical formula food by atomic absorption spectrometry

目的建立一种测定特殊医学配方食品中钾元素含量的原子吸收光谱法。方法该方法采用钾钠混标,研究工作电流、燃烧器高度、光谱通带、燃气流量等操作条件对测定特殊医学用途配方食品中钾含量的影响,确定最佳测试条件。结果优化后测试条件为:采用钾钠混标,不加入铯盐,燃烧头偏转30?,燃烧器高度为3mm,燃气流量为0.9L/min,空心阴极灯电流为8mA,光谱通带为0.6nm,样品测定结果为586.22 mg/100 g,检出限为0.019 mg/L,回收率为96.8%～98.1%,相对标准偏差为0.47%。结论本方法操作简单、准确度、精密度、灵敏度高,能较好的满足特殊医学配方食品中钾元素测定要求。

Objective To optimize the analytical conditions of the method for the determination of potassium in special medical formula food by atomic absorption spectrometry. Methods This method used the mixed standards of sodium and potassium. The effects of operating conditions such as working current, burner height, spectral band and gas flow on the determination of potassium content in formula food for special medical use were studied and the optimal test conditions were determined. Results The optimized test conditions were as follow： the mixed standards of sodium and potassium was used without adding cesium salt, the combustion head deflects was 30°, burner height was 3 mm, gas flow rate was 0.9 L/min, hollow cathode lamp current was 8 mA, and spectrum bandpass was 0.6 nm. The optimized test results were 586.22 mg/100 g. The limit of detection was 0.019 mg/L, and the recovery rates were 96.8%-98.1% with the relative standard deviation of 0.47%. Conclusion This method is simple, and has high accurate, precise and sensitive, which can meet the requirements of the determination of potassium in special medical formula food.