钯(Ⅱ)—硫氰酸钾—罗丹明B分光光度法测定微量钯

SPECTROPHOTOMETRIC DETERMINATION OF PALLADIUM WITH POTASSIUM THIOCYANATE AND RHODAMINE B

研究了在聚乙烯醇存在下,钯与硫氰酸钾和罗丹明B的显色反应.在0.001—0.002mol/LH_2SO_4介质中,生成离子缔合物.最大吸收波长为589nm.表观摩尔吸光系数为2.48×10~5L·mol^(-1)·cm^(-1).钯含量在0—8μg/25mL内服从比尔定律.还研究了多种离子对测定的影响.方法应用于钯——活性炭催化剂中钯的测定.

The chromogenic reaction of palladium with potassium thiocyanate and rhodamine B in the presence of polyvinyl alcohol has been investigated. In a medium of 0.001 0.002M H2SO4 the ion association complex was formed. The maximum absorption wavelength of the complex is at 589nm. Its apparent melar absorptivity is 2.48X 1051 mol-1 cm-1. Beer's law is obeyed in the range 0-8ug/25mL of Pd. The influence of various foreign ions has also been studied. The composition of the ion association complex has been established as [RB+] 2 [Pd(SCN)42-]. The method has been applied to determine the palladium content in the Pd-active carbon catalysts with satisfactory results.