An improvement of selectivity for electrochemical detection of dopamine (DA) with differential pulse voltammetry is achieved by covalently modifying a glassy carbon electrode (GCE) with O-carboxymethylchitosan (OCMCS). The amphiphilic chitosan provides electrostatic accumulation of DA onto the electrode surface. In a phosphate buffer solution (pH 6.0), a pair of well-defined reversible redox waves of DA was observed at the OCMCS/GCE with a ΔEp of 52 mV. The anodic peak current obtained from the differential pulse voltammetry of dopamine was linearly dependent on its concentration in the range of 6.0 × 10-8 to 7.0 × 10-6 M, with a correlation coefficient of 0.998. The detection limit (S/N = 3) was found to be 1.5 × 10-9 M. The modified electrode had been applied to the determination of DA in human serum samples with satisfactory results.
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机译:通过使用O-羧甲基壳聚糖(OCMCS)共价修饰玻璃碳电极(GCE),可以提高差分脉冲伏安法电化学检测多巴胺(DA)的选择性。两亲性壳聚糖将DA静电积累到电极表面上。在磷酸盐缓冲溶液(pH 6.0)中,在OCMCS / GCE处观察到一对清晰可逆的DA氧化还原波,其ΔE> p sub>为52 mV。从多巴胺的差分脉冲伏安法获得的阳极峰值电流在6.0×10 -8 sup>至7.0×10 -6 sup> M范围内线性变化,其浓度与相关系数为0.998。检出限(S / N = 3)为1.5×10 -9 sup>M。该修饰电极用于人血清样品中DA的测定,结果令人满意。
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