羧基化多壁碳纳米管修饰电极伏安法测定多巴胺

Determination of dopamine by voltammetry with multi-wall carbon nanotubes functionalized with carboxylic group modified electrode

目的 :研究用羧基化多壁碳纳米管修饰电极伏安法测定痕量多巴胺 (DA)的效果。方法 :采用涂布法制成羧基化多壁碳纳米管修饰电极 ;在pH =5 .4的KH2 PO4 Na2 HPO4缓冲溶液中 ,采用该修饰电极伏安法测定DA。结果 :该修饰电极对DA有着显著的电催化作用 ,与裸玻碳电极相比较 ,其灵敏度大大提高 ,在2 .0× 10 -7～ 6 .0× 10 -4mol/L浓度范围内 ,DA的氧化峰电流与浓度成良好的线性关系 ,检测限为 5 .0× 10 -8mol/L。将该修饰电极用于盐酸多巴胺针剂的测定 ,相对平均偏差为 1.4 % ,平均回收率为 99.2 %。结论 :该修饰电极响应快 ,灵敏度高 ,稳定性好 ,寿命长 。

Objective:To study a quantitative method for determination of trace dopamine(DA) by voltammetry with multi wall carbon nanotubes fuctionalized with carboxylic group modified electrode(CME).Methods:The CME was fabricated,which based on the immobilization of multi wall carbon nanotubes functionalized with carboxylic group. In a medium of KH 2PO 4 Na 2HPO 4 buffer solution with pH=5.4,the CME was utilized for determination of DA by voltammetry.Results:The CME exhibited efficiently catalytic oxidation for DA. Compared with the bare glass carbon electrode,the CME could increase the sensitivity for the determination of DA. The oxidation currents were linear for DA in the range of 2.0×10 -7 ～6.0×10 -4 mol/L,and the detection limit was calculated to be 5.0×10 -8 mol/L. The CME had been applied to assess the contents of DA in drug with RSD 1.4% and average recovery rate 99.2%.Conclusion:The CME shows high sensitivity,stability and long life,and is suitable for the determination of biologic molecules which have electrical activity.