Ag(Ⅰ)-phen-TPPS_4荧光体系的研究及痕量银的测定

Studies on the Ag (Ⅰ) -phen-TPPS 4 Fluorescene System and Its Application to the Determination of Trace Amounts of Silver

研究了Ag(I)-phen-TPPS_4荧光体系,建立了痕量银的荧光测定新方法。在碱性介质中,Ag(phen)_2^+络阳离子与TPPS_4 的阴离子形成三元离子对缔合物(Ag:Phen:TPPS_4=1:2:1),导致TPPS_4 的荧光(λex=413 nm,λem=638 nm)猝灭而定量测定银。也可直接测定缔合物的荧光(λex=438 nm,λem=648 nm)而定量测定银。两种测定方法在Ag(I)浓度为0～3 μg/25 ml范周内,工作曲线呈良好线性关系,方法的检出限前者为0.88 PPb,后者为5.2 PPb。用于废水中微量银的测定,变异系数6％,标准加入量的回收率 92～107％。

The Ag(I)-phen-TPPS4 fluorescence system has been studied and a new fluorimetric method for the determination of trace amounts of silver has been developed. The method is based on the fact that Aq(phen)2+ complex cation associates with the anion of TPPS4 to form an ion association ternary complex in alkaline aqueous solution, leading to fluorescence-quenching of TPPS4 (λex=4l3 nm,λem=638 nm), and can be used for determining silver. Calibration curve is linear over the concentration ranges of 0-3 μg Ag(I), while the limit of detection is 0.88ppb. The ion association ternary complex has the composition of Ag(I): phen: TPPS4=1: 2: 1. Determination of silver can also be carried out by direct measurement of the fluorecence intensity of the ternary complex(λex=438nm,λem=648nm). The linear response range of concentration is also between 0 and 3 μg Ag(I), and the limit of detection is 5.2 ppb, This method is simple, convenient and guick. It has been used for the determination of silver in waste water, with the variation coefficient of 6% and the recovery of 92-107%.