钯与对若丹宁偶氮苯甲酸络合物的固相萃取和光度测定

Determination of palladium by solid phase extraction and spectrophotometry with p-rhodanineazobenzoic acid

根据新试剂对若丹宁偶氮苯甲酸（RABA）与钯的显色反应及C18固相萃取小柱对显色络合物的固相萃取,建立了一种测定痕量钯的新方法,在pH为2.0～4.0的HCl-邻苯二甲酸氢钾（HCl-KHP）缓冲介质中,在CTMAB存在下,钯与RABA发生反应形成1∶1的稳定络合物,该络合物可用C18固相萃取小柱富集,小柱上富集的络合物用乙醇洗脱后用光度法测定,在富集后的测定液中,络合物最大吸收波长为500 nm,摩尔吸光系数ε=1.36×105L.mol-1.cm-1,Pd2＋量在0.1～1.0μg/mL内符合比尔定律,方法用于催化剂中钯的测定。

Based on the color reaction of p-rhodanineazo benzoic acid （RABA） with palladium（ Ⅱ） and the solid phase extraction of its colored complex with C18 cartridge, a new method for the determination of palladium was studied. In the presence of CTMAB and HC1-KHP buffer solution （pH 2.0 - 4.0） medium. RABA reacts with palladium（ Ⅱ ） to form a stable 1 ： 1 complex. The colored complex was extracted by C18 cartridge and the retained chelate was eluted from cartridge with ethanol, then can be determined by spectrophotometry at 500 nm. Beer＇s law is obeyed in range of 0.1 - 1.0μg/mL and ε is 1.36×10^5L·mol^-1·cm^- 1 . The method was applied to determination of the trace palladium in the Pt/Pd catalysts with a satisfactory result.