十一硼烷十四氢钠和硼氢化钠对过渡及贵金属蒸气发生效率的影响

Effect of Sodium Tetradecahydroundecaborate and Sodium Borohydride on Efficiency Enhancements of Chemical Vapor Generation of Transition and Noble Metals Elements

应用电感耦合等离子体原子发射光谱法研究了增强过渡及贵金属元素Au,Pt,Pd,Co,Zn和Mn的化学蒸气发生效率的两种方法。方法一是使用十一硼烷十四氢钠盐(NaB11H14)代替硼氢化钠(NaBH4)做还原剂,增加了反应物氢的浓度;方法二是在线加热NaBH4和元素的反应溶液,增加了还原反应的速度。方法一的最佳反应条件是:NaB11H14浓度是1.25%(m/V),Au,Pt和Pd最佳酸度是1.0mol/L,而Co,Zn和Mn最佳酸度是0.4mol/L。与NaBH4相比,蒸气发生效率增强最大的是Au(6.3倍),而Mn增强最小(1.9倍),其它元素介于两者之间。方法二中NaBH4最佳用量及最佳反应酸度等反应条件与方法一相似,蒸气发生效率增强最大的是Au(10.2倍),而Co增强最小(3.9倍);元素的蒸气发生效率随温度的升高而增强。NaBH4在90℃获得的蒸气发生效率增强远高于NaB11H14在室温所获得的蒸气发生效率。

Two methods have been investigated to enhance the chemical vapor generation（CVG） of Au,Pt,Pd,Co,Zn and Mn for inductively coupled plasma atomic emission spectrometry.Sodium tetradecahydroundecaborate（NaB11H14） was used instead of sodium borohydride（NaBH4）,which increased the concentration of reductant hydrogen;and the solutions of the metal ions and sodium borohydride were heated to accelerate the reaction.With the first method,the optimal NaB11 H14 concentration was 1.42（m/V）,the optimal HNO3 concentrations were 1.0 mol/L for Au,Pt and Pd and 0.4 mol/L for Co,Zn and Mn.The Au signal was enhanced 6.3-fold.For Mn,the enhancement was a more modest 1.9-fold.The signal enhancements obtained for other elements were between these two elements.With the second method,the optimal concentrations of NaBH4 and HNO3 were the same as the first method,Au signal showed a 10.2-fold enhancement at 90 ℃.Co signal showed the lowest enhancement with a 3.9-fold increase in signal.When the temperature of reactant solution was increased from room temperature to 55.0 ℃ and 90.0 ℃,respectively,the signal of CVG of metal elements showed significant increase with increasing temperature of reactant solution.The results show the method exhibits higher enhancements in the efficiency of CVG than that using NaB11H11 as reductant at 90 ℃ of reaction temperature.