【摘要】 金膜电极阳极溶出伏安法测定痕量砷已有报道,但铜、锑、铋存在严重干扰。本文采用Nafion修饰电极同位镀金膜阳极溶出伏安法测定痕量砷,大大提高了其选择性,铜、锑、铋分别为砷含量的6倍,3倍和6.5倍以下时,不干扰测定;测定灵敏度也较同位镀金膜电极时高。本法应用于标钢和黄河底泥中砷含量的测定,均获得满意结果。更多还原

【Abstract】 This paper reports a sensitive and selective method for the determination of trace arsenic by anodic stripping voltamraetry using simultaneous plated thin gold-film and nafion modified film on the glassy-carbon electrode. The supporting electrolyte chosen consisted of 0.9mol/L HC1 and 9×10^-5mol/L Au（Ⅲ）. The preconcentration was carried out at -0.25V （vs.Ag/AgCl）for 2min. With stirring and arsenic was deposited. Stirring was stopped, and after 30sec. of quiescent time, the stripping peak was recorded by scanning linearly at a sweep rate of 250mV/s trom -0.25V to+0.85V, the peak potential was at about + 0.25V. Under optimum conditions, the stripping peak current is linearly related to the concentration of arsenic in the range of 3～60ng/mL. 6-fold amounts of Cu, 3-fold amounts of Sb and 6.5-fold amounts of Bi can be tolerated, but they interfere seriously on gold film electrode. The method has been applied to determine arsenic in the botton- mud of the Yellow River and steel samples with satisfactory results. The recovery was in the range of 91～110% with relative standard deviations less than 5%.更多还原