高效阴离子色谱法测定电催化氮气氧化中NO_(3)^(-)/NO_(2)^(-)的含量

Determination of NO_(3)^(-)/NO_(2)^(-) in N_(2) electrooxidation by high performance ion chromatography

开发了一种测定高浓度SO^(2-)_(4)电解液(0.5 mol/L)中NO_(3)^(-)/NO_(2)^(-)含量的高效阴离子色谱法。该方法不受催化剂溶出以及其它干扰离子的影响,可以应用于电催化氮气氧化制备NO_(3)^(-)/NO_(2)^(-)。通过改变流动相的流速、淋洗液浓度以及柱温实现了SO^(2-)_(4)与NO_(3)^(-)/NO_(2)^(-)色谱峰的完全分离。优化得到最佳检测条件:流动相流速1.0 mL/min,柱温30℃,淋洗液浓度25 mmol/L,淋洗液设置为等浓度梯度,冲洗因子:10,此条件下在较宽的检测范围内(0~300 mg/L)实现NO_(3)^(-)/NO_(2)^(-)的高灵敏度检测。其中,NO_(3)^(-)线性关系式为:Y_(2)=0.0107X_(2)-0.0255,相关系数R^(2)为0.9998;NO_(2)^(-)线性关系式为:Y1=0.0127X1+0.0107,相关系数R^(2)为0.9997。

A high performance ion chromatography(HPIC)method was developed for the determination of NO_(3)^(-)/NO_(2)^(-) content in the electrolyte containing a large amount of SO_(4)^(2-) ions(0.5 mol/L).The effects of catalyst dissolution and other interfering ions are limited for this method,thus it can be applied to the field of electrocatalytic N_(2) oxidation into NO_(3)^(-)/NO_(2)^(-).The separation of SO^(2-)_(4) and NO_(3)^(-)/NO_(2)^(-) in chromatographic peaks was achieved by changing the flow rate of mobile phase,the concentrations of eluent and the column temperature.The optimized parameters were obtained as mobile phase flow rate of 1.0 m L/min,column temperature of 30 oC,eluent concentration of 25 mmol/L,eluent concentration gradient,and rinse factor of 10.Under the optimal detection conditions,a high sensitivity detection for NO_(3)^(-)/NO_(2)^(-) in a wide range(0-300 mg/L)was achieved.The linear relationship of NO_(3)^(-) was Y_(2)=0.0107 X_(2)-0.0255,with the regression coefficient(R^(2))of 0.9998.The linear relationship of NO_(2)^(-) was Y1=0.0127 X1+0.0107,with the R^(2)of 0.9997.