十二烷基苯磺酸钠存在下铑(Ⅲ)与5-Br-TAMB体系络合吸附波的研究

Adsorptive wave of rhodium(Ⅲ)-2-(5-Br-thiazolyazo) -5-dimethyl-aminobenzoic acid complex in presence of C_(18)H_(29)NaO_3S

在表面活性剂存在下,研究了铑(Ⅲ)与2 (5 溴 2 噻唑偶氮) 5 二甲氨基苯甲酸络合物吸附波.结果表明,在pH=5.0的HAc NaAc缓冲液中,Rh3+ 2 (5 溴 2 噻唑偶氮) 5 二甲氨基苯甲酸络合物有一较灵敏的极谱波,其峰电位Ep为-574mV(vs.SCE),加入表面活性剂十二烷基苯磺酸钠使峰高增加3.7倍,峰电位负移到-584mV(vs.SCE).铑质量浓度在0.15～6.0μg/L范围内与峰电流I′p有良好的线性关系,检出限为0.086μg/L.经多种电化学方法证明该波为络合物吸附波,其电极过程为不可逆过程,电子转移数为2.此外还试验了多种离子对峰电流I′p的影响.所拟方法已用于13X分子筛催化剂中痕量铑的测定.

In pH=5.0 HAc-NaAc butter solution, rhodium(Ⅲ)-2-(5-Br-thiazolyazo)-5(-dimethylamino)-benzoic acid (named 5-Br-TAMB) complex causes a sensitive polarographic wave at the potential of E_p=-574 mV(vs. SCE). In the presence of C_(18)H_(29)NaO_3S, the second-order derivative peak current is largely increased by 3.7 times and moves to -584 mV. It is linear in the range of 0.15～6.0 μg/L for rhodium(Ⅲ)with a detection limit of 0.08 6 μg/L. Several electrochemical methods are used to study the properties of the wave. It is proved to be an adsorptive wave of the rhodium complex. The electrode process is an irreversible reduce process, and the number of electron transfer is 2. The interference of diverse ions on the peak current is investigated. The proposed method has been applied to determine trace rhodium in 13 X sieve catalyzer with a satisfactory result.