微波消解-释放剂辅助火焰原子吸收分光光度法测定蛋白质粉中的钙

摘要

建立采用微波消解-释放剂辅助火焰原子吸收分光光度法（flame atomic absorption spectrophotometry,FAAS）测定蛋白质粉中钙的方法。探讨消解体系、消解压力、消解时间以及增压方式对消解结果的影响,选择硝酸镧为释放剂,研究待测样品中硝酸镧的质量浓度对钙元素释放的影响。结果表明,在最佳的实验条件下,钙的线性范围为1～20μg/mL,检出限为0.15μg/mL,测定蛋白质粉中钙的质量分数为0.46%,精密度为1.63%,加标平均回收率为96.8%,相对标准偏差为2.34%。该方法线性范围宽、相关性好,准确度和精密度高,具有较高的实用价值。%A method has been established for the determination of calcium in protein power using microwave digestion-flame atomic absorption spectrophotometry with La（NO3）3 as the releasing agent.Digestion efficiency was investigated with respect to four variables including digestion system,digestion pressure,digestion time and pressurization style.The effect of La（NO3）3 concentration on the release of calcium was discussed.Under optimal conditions,the linear range of this method for calcium was 1-20μg/mL and the detection limit was 0.15μg/mL.The average calcium content in a commercial protein powder sample determined by this method was 0.46% with a relative standard deviation of 1.63%（n = 6）.The average recovery rate of calcium in a protein powder sample with a calcium content of 9.10μg/mL across the spike levels of 0.5,1.5μg/mL and 2.0μg/mL was 96.8% with a relative standard deviation of 2.34%.Therefore,this method has a wide linear dynamic range,good correlation,high accuracy and precision,and high practical application value.