钼酸铵和乙基罗丹明B光度法测定微量钯

Spectrophotometric Determination of Microamounts Palladium Using Ammonium Molybdate and Ethylrhodamine B Method

本法研究了在聚乙烯醇（ＰＶＡ）存在下，钯与钼酸铵和乙基罗丹Ｂ（ＥＲＢ）反应形成的有色离子缔合物用于微量钯的光度法测定。缔合物的最大吸收位于５８０ｎｍ，表观摩尔吸收系数ε为２．１３×１０５Ｌ·ｍｏｌ－１·ｃｍ－１，钯量在０－５．５μｇ／２５ｍＬ范围内服从比耳定律。体系至少稳定１４０ｈ，检出限（３σ）８．６４μｇ／Ｌ（ｎ＝１１），对０．２０ｍｇ／ＬＰｄ（Ⅱ）测定的相对标准偏差为２．６６％（ｎ＝１２）。缔合物的摩尔比为Ｐｄ∶ＥＲＢ＝１∶４。考查了５０多种共存离子的影响。本法用于炭基和铝基催化剂中微量钯的测定，结果满意。

Palladium with ammonium molybdate and ethylrhodamine B(ERB)to form a colour ionassociation complex in the presence of polyvinyl alcohol(PVA).The maximum absorbance of the ionassociation complex is at 580 nm.Its apparent molar absorptivety is 2.13×10 5L·mol -1 ·cm -1 ,and it is stable far at least 140h. Beer's law is obeyed in the range of 0-5.5μg/25mL for palladium.The limit of detection(3σ) is 8.64μg/L(n=11).The relative standard deviation for the determinations of 0.20mg/L palladium is 2.66%(n=12).The molar ratio of Pd(Ⅱ) to ERB in the ion association complex is 1∶4 by equilibrated movement method.Over 50 coexisting ions were tested for interferences.The system was used for determination of microamounts palladium in some catalyst with satisfactory results.