常见食品中钾、钠测定的方法研究

Determination of potassium and sodium in common foods

中文关键词:  钾  钠  前处理  测定

英文关键词:potassium  sodium  pretreatment

中文摘要:

      目的 针对现行食品中钾、钠测定的国家标准的局限性, 对食品中钾、钠测定的前处理方法和测定方法进行探讨。方法 分别采用4种前处理方法和3种测定方法对普通食品和国家标准物质中的钾、钠进行测定, 并计算和比较各种方法的检出限、精密度和准确度。结果 4种前处理方法测定钾、钠的平均回收率为84%~112%, 精密度为0.4%~3.4%; 3种测定方法测定钾、钠的检出限分别为1.79~10.7 mg/kg和3.68~14.2 mg/kg, 精密度为0.2%~3.8%。结论 4种前处理方法和3种测定方法均能满足食品中钾、钠的检测要求, 且无明显差异。密闭微波消解法和压力罐消解法更适合于钾、钠测定的前处理。在溶液酸度小于5%时, 对于低含量的钾、钠, 火焰原子吸收光谱法更为合适, 而对于高含量的钾、钠, 电感耦合等离子体发射光谱法更为合适。

英文摘要:

      Objective To investigate pretreatment and determination methods of potassium and sodium in foods, aiming at the limitations of determination methods in current national standards. Methods After pretreated by 4 kinds of pretreatment methods, the potassium and sodium in common foods and certified reference materials were determinate by 3 methods. Then the detection limit, precision and accuracy were also calculated and compared. Results The recoveries of 4 kinds of pretreatment methods of potassium and sodium were in the range of 84% to 112%, and the precisions were in ranged of 0.4% to 3.4%. The detection limits of the 3 kinds of determination methods of potassium and sodium were 1.79~10.7 mg/kg and 3.68~14.2 mg/kg, while the precisions ranged from 0.2% to 3.8%. Conclusions Four kinds of pretreatment methods and 3 kinds of determination methods could all meet the detection requirements of potassium and sodium in food and had no obvious differences. Closed microwave digestion and pressure tank digestion methods were more suitable for the determination of potassium and sodium. When solution acidity was less than 5%, flame atomic absorption spectroscopy (FAAS) was more suitable for the determination of low concentrations of potassium and sodium, and inductively coupled plasma atomic emission spectrometry (ICP-OES) was more suitable for the determination of high concentrations of potassium and sodium.