Determination of Hypoxanthine in the Presence of Copper by Adsorptive Stripping Voltammetry

A stripping method for the determination of hypoxanthine in the presence of copper at the submicromolar concentration levels is described. The method is based on controlled adsorptive accumulation of hypoxanthine-copper at the thin-film mercury electrode followed by a fast linear scan voltammetric measurement of the surface species. Optimum experimental conditions were found to be the use of 1.0 × 10﹣3 mol·L﹣1 NaOH solution as electrolyte supporting, an accumulation potential of ﹣0.50 V and a linear scan rate of 200 mV·s﹣1. The response of hypoxanthine-copper is linear over the concentration ranges of 10 - 60 ppb. For an accumulation time of 30 minutes, the detection limit was found to be 250 ppt (1.8 × 10﹣9 mol·L﹣1). Adequate conditions for measuring the hypoxanthine in the presence of metal ions, xanthine, uric acid and other nitrogenated bases were also investigated. The utility of the method is demonstrated by the presence of hypoxanthine associated in ATP or ssDNA.

安息香肟碳糊修饰电极快速线性扫描伏安法测定铜

本文报道了一种用络合剂安息香肟制备的化学修饰电极。由于安息香肟对Cu(Ⅲ)的络合有特殊的选择性,电极可以选择性富集溶液中的Cu(Ⅲ)。经过电位还原,并可采用快速线性扫描伏安法进行定量分析。检测限可达10^(-9)mol/L浓度。采用本文法对成分复杂的阳极泥等样品进行直接测定,得到了令人满意的结果。

多壁碳纳米管修饰玻碳电极测定铜离子

以多壁碳纳米管（ MWCNTs）修饰玻碳电极为工作电极,采用阳极溶出线性扫描法研究了铜离子的电化学测定方法。探讨了MWCNTs修饰层数、富集电位、富集时间、溶液pH、支持电解质对峰电流的影响。实验表明,铜离子浓度在1．0×10-8~1．0×10-5 mol·L-1范围内与峰电流呈良好的线性关系,检测限为2．0×10-9 mol· L-1,且该电极具有良好的稳定性和抗干扰能力。

铋膜修饰玻碳电极用于线性扫描溶出伏安法测定铝箔中痕量镓

用电化学沉积法将铋离子修饰在玻碳电极上,应用此铋膜修饰玻碳电极测定镓时,将试液在pH 5.4的六次甲基四胺-盐酸缓冲溶液中在-1.30 V处预还原40 s,然后在-1.30^-0.50 V范围内扫描,使镓离子从修饰电极上溶出,实现了镓离子的溶出伏安法测定,在-1.01 V处可得镓离子的氧化峰电位,镓的质量浓度在0.002 8~0.21μg.L-1范围内与其峰电流值呈线性关系,方法的检出限(3S/N)为0.7 ng.L-1。方法用于测定铝箔中镓的含量,加标回收率在98.2%~103.8%之间。

米吐尔在聚邻苯二胺负载Nafion@纳米氧化亚铜修饰电极上的电化学行为及测定

研制了一种新型电化学传感器——聚邻苯二胺负载Nafion@纳米氧化亚铜(Cu2ONPs)修饰碳糊电极(Nafion@Cu2ONPs/P-oPD/CPE),在0.2mol/L NaAc-HAc(pH=4.6)溶液中,采用循环伏安法(CV)和线性扫描溶出伏安法(LSSV)研究了米吐尔在该修饰电极上的电化学行为。在最佳条件下,米吐尔的氧化峰电流与其浓度在8.0×10-7~4.0×10-5 mol/L和4.0×10-5~1.0×10-3 mol/L范围内呈良好的线性关系,检出限为4.3×10-7 mol/L。方法用于模拟水样中米吐尔的测定,回收率为99.0%~102.0%。