[PbI_4]^(2-)-CV体系共振瑞利光散射法测定痕量结晶紫

Determination of trace crystal violet by resonance Rayleigh scattering method with [PbI_4]^(2-)-CV system

在硫酸介质中,Pb2+与过量I-形成配离子[PbI4]2-,[PbI4]2-能与结晶紫(CV+)阳离子形成电中性的离子缔合物,使体系的共振瑞利散射(RRS)增强,据此建立一种新的共振瑞利光散射法测定痕量结晶紫的新方法。在0.07 mol/L H2SO4、1.8×10-4mol/L Pb2+、过量I-及0.04%PVA等的存在条件下,RRS强度改变值(ΔI)与结晶紫的浓度在0.15～180μg/mL范围内呈良好的线性关系(r=0.998),方法检出限为0.08μg/mL,RSD<2.5%,样品加标回收率为86.4%～107.3%。新方法灵敏、操作简便,应用于鱼肉和鱼池水中痕量结晶紫的测定,结果满意。

A novel resonance Rayleigh scattering （RRS） trace crystal violet （CV）. In sulfuric acid medium, Pb2＋ method was established for the determination of reacted with excessive I- to form a coordination ion [ PbI4 ] 2- , then [ PbI4 ] 2- reacted with CV cation （ CV ＊ ） results in increasing of RRS. Under the optimal experimental to form electroneutra： ionic associate which conditions which were 0.07 mol/L sulfuric acid, 1.8×10^-4moL/L Pb2＋, excessive I^- and 0.04% polyvinyl alcohol, the enhanced intensity of RRS （AI） was linear to the concentration of CV in the range of 0.15×180 μg/mL with linear relationship,r = 0. 998. The detection limit for CV was 0.08μg/mL and RSD was less than 2.5 %. The recovery rates of samples were 86.4% - 107.3%. This method is simple and sensitive. It can be applied to the determination of trace crystal violet in fish and fish pond water samples with satisfactory results.