摘要
文献[1、2]曾报道了β-CD对显色体系的影响,但有机溶剂对于β-CD存在显色体系的影响至今未见报道。本文研究了乙醇存在下,锌与5-Br-PADAP-β-CD的显色反应。实验表明,乙醇对此显色反应有明显的增敏作用。形成络合物的适宜pH范围为7.5—10.5,络合物的最大吸收波长为552nm,表现摩尔吸光系数为1.35×10~5L·mol^(-1)·cm^(-2),较无乙醇存在的三元体系灵敏度增大了1.6倍。锌在0-16μg/25ml范围内服从比尔定律。显色体系在四小时内保持稳定。用该法测定了水样中微量锌,得到令人满意的结果。
In this paper, the effect of EtOH on color reaction of Zn-5-Br-PADAP-α-CD has been studied in detail At pH 9.0, in the presence of EtOH. The complex has an absorption maximum at 552 nm. The molar absorptivity is 1.35 × 105L · mol-1 ·cm-1. Beer's law is obeyed for zinc in the range 0-16 μg/25ml. The colour of solutions is stable for at least 4 hours. The method has been used to determine zinc in water without separation.
