用银-色氨酸复合膜修饰玻碳电极循环伏安法测定去甲肾上腺素

在含有1.0mmol.L-1硝酸银、5.58×10-2 mol.L-1色氨酸的溶液中,于-0.8～1.8V(vs.Ag/AgCl)电位下,在玻碳电极表面电沉积一层银-色氨酸复合膜,制得银-色氨酸复合膜修饰玻碳电极(Ag-TRY/GCE)。采用扫描电镜对电极表面的性能进行表征,循环伏安法对其电化学性能进行研究。试验发现:在pH 6.0磷酸盐缓冲溶液中,去甲肾上腺素(NE)在修饰电极出现一对明显的氧化还原峰,氧化峰电位为0.306V,还原峰电位为0.368V,提出了用循环伏安法测定NE的方法。在试验条件下,氧化峰电流与去甲肾上腺素浓度在3.4×10-7～8.3×10-6 mol.L-1和8.3×10-6～1.1×10-4 mol.L-1两段范围内呈线性关系,检出限(3S/N)为4.3×10-8 mol.L-1。修饰电极用于药物中去甲肾上腺素的测定,加标回收率在95.6%～99.4%之间。

Cyclic Voltammetric Determination of Norepinephrine with Ag-Tryptophan Compound Film Modified Glassy Carbon Electrode

The modified electrode(Ag-Try/GCE) was prepared by electrodeposition of a film of silver and poly-tryptophan on the surface of glassy carbon electrode at the potential range from-0.8 V to 1.8 V(vs.Ag/AgCl) from a solution containing 1.0 mmol·L-1 AgNO3 and 5.58×10-2mol·L-1 tryptophan.The surface property of the modified electrode was characterized by scanning electron microscopy,and its electrochemical property studied by cyclic voltammetry.It was found that a pair of significant oxidation and reduction peaks of NE was observed at the Ag-Try/GCE with the Epc at 0.306 V and Epa at 0.368 V in PBS of pH 6.0.Based on these findings,a selective method for determination of NE by cyclic voltammetry was proposed.Under the optimized experimental conditions,linear relationship between values of oxidation peak current and concentration of NE was obtained in 2 segmental ranges of 3.4×10-7-8.3×10-6mol·L-1 and 8.3×10-6-1.1×10-4mol·L-1,with detection limit(3S/N) of 4.3×10-8mol·L-1.The proposed method was used in the determination of NE in medicine,giving values of recovery found by standard addition method in the range of 95.6%-99.4%.