植物种子中微量钼的电化学发光分析法测定研究

摘要

[Objective] This study aimed to establish an electroehemiluminescence method for determining the trace molybdenum content in plant seeds. [ Method] The equipment used in this study consists of an electrogenerated reagent system and a flow injection chemiluminescenc detection system. The optimal electrir, potential, reagent acidity, sample solution flow rate, as well as the concentration and alkalinity of the luminal were screened to measure the trace molybdenum content in plant seeds. [ Result] The unstable molybdenum (III) was on-line electro-generated from molybdenum (VI) via controlled potential electrolysis technique using a homemade flow-through carbon electrolytic cell at the potential of -0.60 V (us Ag/AgCl). The method allows the determination of 5.0 × 10-10 -5.0 × 10-7 g/ml molybdenum with a detection limit of 5 ×10-7 g/ml molybdenum. The relative standard deviation is 2.6% for the 1.0 ×10-9 g/ml molybdenum solution in 11 measurements. [Conclusion] Compared with previous methods, this electrochemiluminescenre method not only improved the selectivity, but also avoided the use of toxic reagent mercury.%[目的]对测定植物种子中微量钼的电化学发光分析法进行研究.[方法]试验所用的仪器由一个电生试剂系统和一个流动注射化学发光检测系统组成,筛选仪器运行所需的最佳电解电位、试液酸度、鲁米诺的浓度和碱度、试液流速,并在此基础上对种子样品中的钼含量进行分析.[结果]在-0.60 V(vs:Ag/AgCl)下恒电位电解还原钼(Ⅵ)为钼(Ⅲ),钼(Ⅲ)与鲁米诺在碱性条件下产生化学发光,发光强度与钼(Ⅵ)的浓度呈线性正相关,从而建立了钼的流动注射电化学发光分析法.该方法的线性范围为5.0×10-10～5.0×10-7g/ml,检出限为5×10-11g/ml钼(Ⅵ),对1.0×10-5g/ml钼(Ⅵ)进行11次测定,得到相对标准偏差为2.6％.将该方法用于植物种子中微量钼的测定,效果较好.[结论]该方法与以前测定钼的化学发光分析法相比,不仅提高了方法的灵敏度,而且在一定程度上提高了方法的选择性,且避免了有毒试剂汞的使用.