针式碳纤维微型传感器的制作与单胺类神经递质分析

DEVELOP OF NEEDLE CARBON FIBER MICROELECTRODES FOR IN VIVO AND DETERMINATION OF NEUROTRANSMITTERS AND ASCORBIC ACID

目的 用自制的针式碳纤维微型传感器测定脑神经递质。方法 采用电化学处理碳纤维微电极方法。结果 获得了高的灵敏度和分辨率。抗坏血酸 (AA)峰与多巴胺 (DA)峰在伏安曲线上完全分离 ,峰电位间隔达 0 16V左右 ,可消除AA对测定的干扰。用微分常规脉冲伏安法测定了活体大鼠脑细胞间液内AA ,3,4 -二羟基苯乙酸 (DOPAC)和 5 -羟吲哚乙酸 (5 -HIAA) ,各自的浓度分别为 1 9× 10 - 4mol·L- 1,3 2× 10 - 5mol·L- 1,3 5× 10 - 6 mol·L- 1。

Objective Determination of neurotransmitters and ascorbic acid for needle carbon fiber microelectrodes was reported.Methods The treatment was simple,at initial a potential of 0.0V,amplitude of 3.0V for 20s,and then a potential of-0.8V for 10s,+1.5V for 10s were applied to the electrode.Results After activation,the pretreated electrode showed very high sensitivity and selectivity.Conclution The detection limit of 5×10 -8 mol·L -1 for dopamine (DA)in phosphate bufer solution (pH7.4)was found.The potential deviation of ascorbic acid(AA)peak from DA peak was 160mV.The Differential Normal Pulse voltammetry was used for in vivo determeination in the rat brain.three peaks at +0.22V,+0.38V and+0.53V were recognized as ascorbic acid,3,4-dihydroxyphenylacetic acid (DOPAC)and 5-hydroxyindoleacetic acid(5-HIAA),and their concentrations were 1.9×10 -4 mol·L -1 3.2×10 -5 mol·L -1 ,3.5×10 -6 mol·L -1 respectively.