Farias Percio A M, Wagener Angela de Luca Rebello, Bastos Margarida Bethlem R, Silva Adriana Tabet da, Castro Arnaldo Aguiar
Departament of Chemistry, Pontificia Universidade Católica, Rua Marquês de São Vicente, 225, CEP 22453-900 Rio de Janeiro, Brazil.
Talanta. 2003 Dec 23;61(6):829-35. doi: 10.1016/S0039-9140(03)00376-X.
The cathodic adsorptive electrochemical behavior of guanine in the presence of some metal ions at the static mercury drop electrode was investigated. A 1.0x10(-3) mol l(-1) NaOH or a 2.0x10(-2) mol l(-1) Hepes buffer at pH 8.0 solutions were used as supporting electrolytes. The reduction peak potential for guanine was found to be around -0.15 V, which is very close to the mercury reduction wave. A new peak appears at -0.60 V in the presence of copper or at -1.05 V in the presence of zinc. A square wave voltammetric procedure for electroanalytical determination of guanine in 2.0x10(-2) mol l(-1) Hepes buffer at pH 8.0 containing 1.6x10(-5) mol l(-1)of copper ions, was developed. An accumulation potential of -0.15 V during 270 s for the prior adsorption of guanine at the electrode surface was used. The response of the system was found to be linear in the range of guanine concentration from 6.62x10(-8) to 1.32x10(-7) mol l(-1) and the detection limit was 7.0x10(-9) mol l(-1). The influence of DNA bases such as adenine, cytosine and thymine was also examined. Cyclic voltammetry was used to characterize the interfacial and redox mechanism.
研究了鸟嘌呤在一些金属离子存在下于静态汞滴电极上的阴极吸附电化学行为。使用1.0×10⁻³ mol·L⁻¹ NaOH或pH 8.0的2.0×10⁻² mol·L⁻¹ Hepes缓冲溶液作为支持电解质。发现鸟嘌呤的还原峰电位约为 -0.15 V，这与汞还原波非常接近。在有铜存在时，在 -0.60 V出现一个新峰；在有锌存在时，在 -1.05 V出现一个新峰。建立了一种方波伏安法，用于在含1.6×10⁻⁵ mol·L⁻¹铜离子的pH 8.0的2.0×10⁻² mol·L⁻¹ Hepes缓冲溶液中对鸟嘌呤进行电分析测定。采用 -0.15 V的富集电位在270 s内使鸟嘌呤预先吸附在电极表面。发现该系统的响应在鸟嘌呤浓度为6.62×10⁻⁸至1.32×10⁻⁷ mol·L⁻¹范围内呈线性，检测限为7.0×10⁻⁹ mol·L⁻¹。还研究了腺嘌呤、胞嘧啶和胸腺嘧啶等DNA碱基的影响。采用循环伏安法表征界面和氧化还原机理。
