【摘要】 在pH 1 0 ,0 0 4mol/L的NH3·H2 O NH4 Cl缓冲溶液中 ,钴 百里香酚酞在NaNO2 存在下 ,于 -1 2 5V (vs SCE)产生一尖锐、灵敏的二次导数极谱波 ,峰电流与钴 (Ⅱ )浓度在 5 0× 1 0 - 8～ 5 0× 1 0 - 6 mol/L范围内呈线性关系 ,检出限为 2 0× 1 0 - 8mol/L。研究了该波的性质 ,证明该波为吸附波。方法用于维生素B12 中痕量钴的测定 ,结果满意更多还原

【Abstract】 In 0.04 mol/L NH 3·H 2O-NH 4Cl buffer solution,at pH 10,a sensitive second derivative polarographic of the complex of Co(Ⅱ)-thymol phthalein-nitrite appears at -1.25 V(vs SCE).The peak current is proportional to cobalt concentration in the range of 5.0×10 -8～5.0×10 -6 mol/L,the detection limit is 2.0×10 -8 mol/L.Several electrochemical methods have been used to study the properties of the polarographic wave.It is proved that the wave is a adsorptive one.This method has been successfully applied to the determination of trace cobalt in vitamin B 12.更多还原