多壁纳米碳管修饰玻碳电极不可逆双安培法测定Fe~（3＋）

摘要

在玻碳电极上成功制备了多壁碳纳米管（MWNTs）修饰玻碳电极（GCE）,并对其进行显微表征。研究表明,该修饰电极（MWNTs/GCE）对Fe3＋具有明显的电催化还原作用。将其用于流动注射不可逆双安培（FI-IB）体系的构建,即：利用Fe3＋在MWNTs/GCE上的还原和硫酸羟胺（（NH2OH）2.H2SO4）在另一支金电极上的氧化,构建了双安培检测新体系,建立了在外加电压为0 V条件下流动注射双安培法直接测定Fe3＋的新方法。在0 V外加电位差下,在6×10-2 mol/L HCl载液中,该还原峰峰电流与Fe3＋浓度在4.0×10-3～10-1mg/mL范围内呈良好的线性关系,其线性回归方程为i（nA）=1.4456×105C-582.97（r=0.9992,n=7）,方法检出限为8.0×10-4mg/mL（S/N=3）。连续测定1.00×10-2mg/mL的Fe3＋标准溶液20次,电流值RSD为2.99%,进样频率为90样/h。该方法具有较高的选择性和灵敏度。对模拟样品中Fe3＋含量的测定,结果比较满意。%The multi-walled carbon nanotubes（MWNTs） modified glassy-carbon electrode（MWNTs/GCE） was prepared and the micrographs of the MWNTs/GCE were obtained by scanning electron microscopy.The modified electrode showed an excellent electro-catalytic effect on the reduction of iron（Ⅲ）.Based on the reduction of iron（Ⅲ） at MWNTs/GCE and oxidation of（NH2OH）2·H2SO4 at the Au electrode,a novel flow injection irreversible biamperometric method was developed for the determination of iron（Ⅲ） under the potential difference of 0 V imposed between two electrodes.In 6×10-2 mol/L HCl,the reduction peak current increased linearly with the concentration of iron（Ⅲ） in the range of 4.0×10-3~10-1 mg/mL,the linear regression equation was i（nA）=1.4456×105C-582.97（r=0.9992,n=7）with a sampling frequency of 90 samples per hour.The detection limit for iron（Ⅲ） was 8.0×10-4 mg/mL and the RSD was 2.99 %.The presented method has the advantage of high selectivity and sensitivity.The analysis of iron（Ⅲ） was performed with satisfactory results.