微波消解-浓度直读法快速测定食品中微量钙的含量

Rapid determination of micro-calcium in food by microwave digestion-concentration direct reading method

中文关键词:  离子选择性电极  浓度直读法  微波消解  微量钙  含量分布

英文关键词:ion selective electrode  direct reading concentration method  microwave digestion  micro-calcium  content distribution

中文摘要:

      目的 建立微波消解-浓度直读法快速测定食品中的微量钙含量。方法 采用硝酸-过氧化氢混合酸进行微波消解, 采用pCa-1钙离子选择性电极快速测定钙含量, 同时研究了钙在不同食品组织中的分布。 结果 最佳条件为: 硼砂-硼酸缓冲剂加入量为3.5 mL, pH为7.4, 1 mol/L三乙醇胺-盐酸离子强度调节剂加入量为5 mL。所用电极性能良好, 平行测定的相对标准偏差小于2.3%(n=5, 干基), 回收率为89.6%~96.0%, 所测定干基样品中钙的含量为0.09~2.64 mg/g, 同一样品中的钙含量呈现由外至内逐渐减小的趋势。结论 该法快速简便、成本低廉、读数直观准确, 有利于现场即时测定。

英文摘要:

      Objective To establish a method for the rapid determination of micro-calcium by microwave digestion-concentration direct reading method. Methods Nitric acid-hydrogen peroxide solution was used for microwave digestion, and calcium was determined rapidly by pCa-1 calcium selective electrode. Meanwhile the calcium distribution was studied in different food organizations. Results Optimal conditions were as follows: the amount of borax and boric acid buffer was 3.5 mL, pH was 7.4, and the amount of ionic strength regulator of triethanolamine and hydrochloric acid (1 mol/L ) was 5 mL. The performance of electrode was good. The relative standard deviations were less than 2.3% (n=5, dry basis), recoveries were ranged from 89.6% to 96.0%, and the calcium content of samples were ranged from 0.09 mg/g to 2.64 mg/g. Calcium content in the same sample presented decreasing trend from outside to inside. Conclusion This method is rapid, simple, inexpensive, intuitive and accurate in reading, which is beneficial to on-site determination.