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本文研究了NH_3-NH_4Cl溶液中铜在稳定玻璃碳电极上的线性变势阴极伏安特性。确定铜氨络离子在玻璃碳电极上的还原分两步进行。在2.5MNH_3-0.75MNH_4Cl中,第一个波是Cu(NH_3)_4~(2+)可逆地还原到Cu(NH_3)_2~+,其峰电势为-0.28伏,与理论值一致。峰电流与电势变化速度及浓度的关系符合Randles-evcik方程。第二个波是Cu(NH_3)_2~+不可逆地还原为铜,当电势变化速度改变时,其峰电势在-0.69～-0.84伏之间。第一个波峰电流的相对标准误差不大于±2.4％,温度系数约为+1.3％/度。本文在氨性底液中用铜在玻璃碳电极上还原的第一个波以测定铜矿中的铜。在极谱法中用的第二个波有[Co(NH_3)_6]~(3+)前波及Tl~+重波,它们在第一个波中均变为后波,从而克服了它们对铜测定的干扰。测定结果与标准样的数据吻合,与示波极谱的数据一致。测定矿样的相对标准误差在±0.37～3.2％之间,符合矿石分析的要求。
In this paper, the linear voltammetric behavior of copper on stabilized glassy carbon electrode in NH_3-NH_4Cl solution was investigated. Determine the reduction of cuprammonium ions on the glassy carbon electrode in two steps. In 2.5MNH_3-0.75MNH_4Cl, the first wave is Cu (NH_3) _4 ~ (2+) reversibly reduced to Cu (NH_3) _2 ~ + with a peak potential of -0.28V, consistent with the theoretical value. Peak current and potential changes in the speed and concentration in line with the Randles-evcik equation. The second wave is Cu (NH_3) _2 ~ + irreversibly reduced to copper, when the rate of change of potential changes, the peak potential of -0.69 ~ -0.84 volts. The first peak current relative standard error of not more than ± 2.4%, the temperature coefficient of about + 1.3% / degree. This article uses the first wave of copper reduction on glassy carbon electrodes in an ammoniacal solution to determine the copper in the copper mine. The second wave used in polarography has [Co (NH_3) _6] ~ (3+) pre-waves and Tl ~ + heavy waves, both of which become back waves in the first wave, thus overcoming them Copper determination of interference. The results are in good agreement with those of the standard samples and are consistent with those of oscillopolarographic data. The relative standard error of determination of ore samples is between ± 0.37 ~ 3.2%, which meets the requirements of ore analysis.