示波极谱溶出法直接测定镍中痕量镉和铊

<正> 痕量镉或铊的极谱测定方法很多,但对于镍中ppb级的镉,二次导数法和催化法灵敏度不够,阳极溶出法需除去基本元素镍。等不经分离直接测定镍中铊,我们的实验证明,镍量不能高于0.03M(约1.7mg/ml),且在酸性条件下易受到镉波干扰。如果用表面活性剂抑制镉波测定铊,铊波在-0.45伏左右(静汞滴电极上),易受铅波干扰。用EDTA掩蔽镉、铅、镍,因其溶解度限制,允许镍浓度不可能太大,且又

DGTGRMINATION OF TRACG CADMIUM AND THLLIUM IN NICCKEIBY LINCAR SWEEPING ANODIC STIPPNG VOITAMMETRY

Cd and Tl in nickel have been determined simultaneously wish ASV on mercuryplated glassy carbon electrode by single linear sweeping polarograph without prior separation.The suitable conditions of determination are in the 0.08M citrate—0.015M NTA—1M NH_4Cl—5×10~(-5)M Hg(NO_3)_2 at pH=2.8 for Cd and in the 0.08M citrate—0.21 M NTA—1M NH_4Cl—5×10~(-5)M Hg(NO_3)_2 at pH=7.3 for Tl. The peak potentials of Cd and TL appear at about -0.72V (VS.SCE) and—0.65V (VS.SCE), respectively. The detection limits of the determination are n×10~(-11)g/ml, the variation coefficients are less than 8.8%, the recoveries are 93%—124%。