Electrochemistry Research Group, Department of Chemistry, St. Joseph's College, Lalbagh Road, Bangalore 560027, Karnataka, India.
Colloids Surf B Biointerfaces. 2013 Oct 1;110:458-65. doi: 10.1016/j.colsurfb.2013.03.056. Epub 2013 Apr 25.
A modified carbon paste electrode (CPE) for the selective detection of dopamine (DA) in presence of large excess of ascorbic acid (AA) and uric acid (UA) at physiological pH has been fabricated by bulk modification of CPE with multi-walled carbon nanotubes (MWCNTs) followed by electropolymerization of glycine (Gly). The surface morphology is compared using SEM images. The presence of nitrogen was confirmed by the energy dispersion X-ray spectroscopy (EDS) indicating the polymerization of Gly on the surface of the modified electrode. The impedance study indicates a better charge transfer kinetics for DA at CPE modified with MWCNT/polyglycine electrode. The presence of MWCNTs in carbon paste matrix triggers the extent of electropolymerization of Gly and imparts more selectivity towards DA by electrochemically not sensing AA below a concentration of 3.1×10(-4)M. Due to the exclusion of the signal for AA, the interference of AA in the determination of DA is totally ruled out by DPV method which is used for its detection at lower concentrations. Large peak separation, good sensitivity, reproducibility and stability allow this modified electrode to analyze DA individually and simultaneously along with AA and UA. Detection limit of DA was determined from differential pulse voltammetric (DPV) study and found to be 1.2×10(-8)M with a linear dynamic range of 5.0×10(-7)M to 4.0×10(-5)M. The practical analytical application of this electrode was demonstrated by measurement of DA content in dopamine hydrochloride injection and human blood serum.
一种改良的碳糊电极（CPE），通过 CPE 与多壁碳纳米管（MWCNTs）的整体修饰，随后电聚合甘氨酸（Gly），可在生理 pH 下选择性检测多巴胺（DA），同时存在大量抗坏血酸（AA）和尿酸（UA）。使用扫描电子显微镜（SEM）图像比较表面形态。能量色散 X 射线光谱（EDS）证实了氮的存在，表明 Gly 在修饰电极表面聚合。阻抗研究表明，在 MWCNT/聚甘氨酸修饰的 CPE 上，DA 的电荷转移动力学更好。MWCNTs 在碳糊基质中的存在引发 Gly 的电聚合程度，并通过电化学方式在低于 3.1×10（-4）M 的浓度下不检测 AA，从而赋予对 DA 更高的选择性。由于 AA 的信号被排除，因此差分脉冲伏安法（DPV）完全排除了 AA 在 DA 测定中的干扰，该方法用于检测较低浓度的 DA。大的峰分离、良好的灵敏度、重现性和稳定性使该修饰电极能够单独和同时分析 DA 以及 AA 和 UA。通过差分脉冲伏安法（DPV）研究确定了 DA 的检测限，为 1.2×10（-8）M，线性动态范围为 5.0×10（-7）M 至 4.0×10（-5）M。通过测量盐酸多巴胺注射液和人血清中的 DA 含量，证明了该电极的实际分析应用。
