【摘要】 <正> 5-[（3,5-二氯-2-吡啶）偶氮]-2,4-二氨基甲苯（简称3,5-Cl₂-PADAT）是光度法测定微量钯和钴的优秀试剂。在十二烷基苯磺酸钠（简称SDBS）存在下,用于镍、铜（Ⅱ）和汞（Ⅱ）的测定,也具有较高的灵敏度和较好的选择性。在SDBS存在下,银也能与3,5-Cl₂-PADAT发生显色反应。在Ag（Ⅰ）-3,5-Cl₂-PADAT-SDBS体系中引入TritonX-200还可以进一步提高显色反应的灵敏度。本文对于Ag（Ⅰ）-3,5-Cl₂-PADAT-Triton X-200新显色体系作了系统的研究。在pH3.5-4.5的范围内形成稳定的四元络合物。在四元络合更多还原

【Abstract】 The optimum conditions for the colour reaction of Ag（I）-3, 5-Cl₂-PADAT SDBS-Triton X-200 have been studied systematically. In a citrate buffer lution of pH 3.5 to 4. 5, Ag（I） forms a red quaternary complex with 3,5-Cl₂PADAT in the presence of SDBS and Triton X-200. The maximum absorption of the complex is at 490nm, and its apparent molar absorptivity is 5.4×10⁴ 1. mo1^-1·cm^-1. The ratio of Ag（I）to 3,5-C1₂-PADAT to SDBS has been establi shed to be 1:4:4. Beer＇s law is obeyed in the range of 2.5 to 25 μg/25ml. Interference from Fe³⁺, Al³⁺, Pd²⁺, Co²⁺, Ni²⁺, Cu²⁺, etc, can be eliminated by using CyDTA as masking agent. The method has been applied to the spectrophotometric determination of silver in ores.更多还原