论文部分内容阅读
镉的极谱测定,通常在氨性或酸性底液中进行,但对微量镉的测定,这些方法的灵敏度尚不能满足要求。近年来,文献[1,2]报导在pH6的碘化钾-六次甲基四胺体系中进行微量镉的催化极谱测定,大大提高了灵敏度,但大量铁对镉仍有吸附。我们通过试验发现,镉在盐酸-碘化钾体系中有一个对称性好、波峰尖锐的吸附催化波,当加入四乙基碘化铵后镉的灵敏度又有提高。本文研究镉在盐酸-碘化钾-四乙基碘化铵体系中产生催化波的最佳条件及催化波的特征。在此体系的选定条件下,镉的峰电位为-0.7伏(对
Polarographic determination of cadmium, usually in the ammonia or acidic bottom liquid, but the determination of trace amounts of cadmium, the sensitivity of these methods can not meet the requirements. In recent years, the literature [1,2] reported the catalytic polarographic determination of trace cadmium in pH 6 potassium iodide-hexamethylenetetramine system, which greatly enhanced the sensitivity, but a large amount of iron still adsorbed on the cadmium. We found through experiments that cadmium has a good symmetry in the hydrochloric acid - potassium iodide system, sharp peak absorption catalytic wave, when added tetraethylammonium iodide sensitivity of cadmium has increased. In this paper, the optimum conditions for the catalytic oxidation of cadmium in hydrochloric acid-potassium iodide-tetraethylammonium iodide system and the characteristics of the catalytic wave were studied. Under the chosen conditions of this system, the peak potential of cadmium is -0.7 volts (pair