论文部分内容阅读
目的建立高效液相色谱-电感耦合等离子体质谱法测定大米中无机砷的分析方法。方法采用两种前处理方法对大米中的无机砷进行提取,经高效液相色谱分离后,利用电感耦合等离子体质谱进行测定。同时对大米样品进行微波消解后测定其中的总砷,通过无机砷及有机砷的总和计算两种前处理方法的回收率,从而对前处理方法进行比较。对磷酸二氢铵、碳酸铵以及磷酸氢二铵等缓冲盐进行选择,并对p H值进行优化,确定最优的流动相条件。结果以12.5 mmol/L磷酸氢二铵作为流动相,调节流动相p H为8.5,流速为1 m L/min,可以将5种无机砷形态完全分离。对两种前处理方法进行比较,发现两种前处理方法的提取效率均大于87.5%,其中酸-热辅助提取法的提取效率相对更高。结论该方法准确、简单,适合大米中无机砷的测定。
Objective To establish a method for the determination of inorganic arsenic in rice by high performance liquid chromatography-inductively coupled plasma mass spectrometry. Methods Two kinds of pretreatment methods were used to extract inorganic arsenic in rice. After separated by high performance liquid chromatography, the content of inorganic arsenic in rice was determined by inductively coupled plasma mass spectrometry. At the same time, the total arsenic in the rice sample was determined by microwave digestion. The recovery of the two pretreatment methods was calculated by the sum of inorganic arsenic and organic arsenic. The pretreatment methods were compared. The choice of buffer salts such as ammonium dihydrogen phosphate, ammonium carbonate and diammonium hydrogen phosphate, and optimization of the p H value, determine the optimum mobile phase conditions. Results With 12.5 mmol / L ammonium dihydrogen phosphate as mobile phase, the mobile phase p H was 8.5 and the flow rate was 1 m L / min. Five inorganic arsenic species could be completely separated. The comparison of the two pretreatment methods showed that the extraction efficiencies of both pretreatment methods were more than 87.5%, and the extraction efficiency of acid-heat assisted extraction method was relatively higher. Conclusion The method is accurate, simple and suitable for the determination of inorganic arsenic in rice.