溴代磺酸偶氮Ⅲ分光光度法测定微量钯
SPECTROPHOTOMETRIC DETERMINATION OF PALLADIUM USING BROMO-SULPHONAZO Ⅲ AS CHROMOGENIC REAGENT
-
摘要: 研究了在邻苯二甲酸氢钾-盐酸缓冲溶液中,3,6-双(4-溴-2-磺基-苯偶氮)-4,5-二羟基-2,7-萘二磺酸与钯(Ⅱ)的显色反应.结果表明,钯(Ⅱ)与溴代磺酸偶氮Ⅲ形成1∶1的蓝色络合物,其最大吸收波长为623.7 nm,表观摩尔吸光系数ε=6.375×104L·cm-1·mol-1,钯含量在0-32 μg/25 mL范围内符合比耳定律,检出限为2.13 μg·L-1.用于钯催化剂中微量钯的测定,结果与AAS法测定值相符.Abstract: A method of spectrophotometric determination of palladium was proposed on the basis of the chromogenic reaction of Pd(Ⅱ) with bromo-sulphonazoⅢ (Br-SAⅢ) in a medium of pH 2.9 buffer solution to form a blue complex with an apparent molar absorptivity of 6.375×104L·mol-1·cm-1 at 623.7 nm.The composition of the color complex was determined by the method of molar ratio and the method of continuous variation.Beer′s law was obeyed in range of 0-32 μg Pd in 25 mL solution.Detection limit of the method was 2.13 μg·L-1 for Pd.The proposed method has been applied to the determination of Pd-catalyst giving results in consistency with the results obtained by AAS method.