银-邻二氮菲-二溴荧光素光度法测定银的含量

摘要

研究了银-邻二氮菲-二溴荧光素离子缔合物体系在水溶液中的显色反应.在pH7.1NH4Ac缓冲介质中,PVA-124存在下,形成1∶2∶1型红色的离子型缔合物,λmax=540nm,ε=4.29×104L.mol-1.cm-1,银含量在0～50μg/25mL范围内符合比尔定律，在EDTA存在下本文提出的测定银的新方法选择性好、灵敏度高,用于相纸、废定影液和废水中银的测定,有很好效果。%The color reaction of bibromoflurescein and O-phenanthroline withsilver(Ⅰ) was studied. In the presence of PVA-124,an red stable ion complex formed in molar ratio 1∶2∶1 at pH7.1(ammonium acetate buffer solution) by associated the silver(Ⅰ) with O-phenanthroline and bibromoflurescein.The apparent molar absorptivity is 4.29×104 at the maximum absorption wavelength 540nm.Beer's law is obeyed in the range of 0～50μg/25mL for silver(Ⅰ).The method has a high selectivity and sensitivity in the presence of EDTA and has been applied to the determination of silver in photographic paper，fixer waste and industrial waste water with satisfactory results.