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

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.