电化学法定性与定量分析水溶液中的微量硼氢根

Electrochemically Qualitative and Quantitative Analysis of Microscale BH_4^- in Aqueous Solution

采用循环伏安法分析了硼氢化钠(Na BH_4)在金(Au)电极上的电化学氧化还原行为,在-0.473 V电位处发现了比较明晰且稳定的BH_4^-特征氧化峰,可作为BH_4^-存在的定性判据。通过线性伏安扫描,对浓度为1.0×10^(-4)~9.0×10^(-3)mol/L的Na BH_4碱性溶液进行了测定,发现Na BH_4特征氧化峰的峰值电流与其浓度呈良好的线性关系,相关系数为0.998 4。利用线性伏安法分别对5.0×10^(-4)mol/L Na BH_4+0.10 mol/L Na OH溶液和5.0×10^(-3)mol/L Na BH_4+0.10 mol/L Na OH溶液平行测定5次,所得结果的平均相对误差分别为3.18%和1.63%,相对标准偏差分别为2.38%和1.88%。

The electrochemical redox behaviors of sodium borohydride(NaBH_4)over Au electrode were investigated by cyclic voltammetry(CV).A distinct and stable peak characterizing the oxidation of BH_4^- was discerned at -0.473 V potential,which was served as the qualitative criterion for recognizing BH_4^-.By means of linear sweep voltammetry(LSV),it was found that the peak currents of the characteristic oxidation peak revealed a good linear relationship with BH_4^- concentration in the range from 1.0×10^(-4)mol/L to 9.0×10^(-3)mol/L,with the correlation coefficient of 0.998 4.For both 5.0×10^(-4)mol/L and 5.0×10^(-3)mol/L NaBH_4 electrolyte system(with 0.10 mol/L Na OH),five LSV parallel measurements give the mean relative errors of 3.18% and 1.63%,relative standard deviations of 2.38% and 1.88%,respectively.