本文研究了一种基于干灰化法和比色法的空心胶囊中铬含量快速测定方法及相应的便携式比色分析仪.实验中考察了显色体系内各试剂浓度、显色时间和显色温度等条件,结果表明溶液中铬浓度在0.01 ～ 1.5 mg/L范围内时体系线性关系良好,相关系数r=0.99945;采用标准加入法对样品灰化时间进行了优化,结果表明灰化时间为3 h时,回收率可达到最佳水平97.15％.为保证仪器的便携性,在设计中采用峰值波长为520 nm的超高亮发光二极管(LED)作为光源,采用锂电池作为电源,采用非色散方案简化光路.与国家标准方法(微波消解—石墨炉原子吸收法)的实际样品比对结果表明,本文方法测定结果的相对误差小于5％,适于对空心胶囊中铬含量的快速测定.%In this paper, a novel method for rapid determination of total chromium in empty capsule based on routine dry ashing method and colorimetric method is proposed. A portable analyzer was developed with a ultra-bright light-emitting diode (LED) emitting at a peak wavelength of 520 nm, a lithium battery and a non-dispersive, integrated optical design. Effects of reagent concentrations, time and temperature of coloration on determination of total chromium were studied respectively. Under the optimal conditions, the calibration curves showed a good linearity in the concentration range of 0.01-1.5 mg/L of total chromium, and the correlation coefficient was 0.99945. Ashing time of the samples was optimized by standard addition method, and the results showed that the best spike recovery was 97.15% at a ashing time of 3 h. Compared with the GB national standard methods (microwave digestion-graphite furnace atomic absorption spectrometry), the results of this method has a maximum relative standard error less than 5%.
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