FAAS Determination of Palladium with FI-On-line Pre-enrichment

Preparation of a micro-column filled with model 717 ion-exchange resin,which was covered with a thin membrane of dimethylglyoxime dispersed in PVC,was described and used for the separation and pre-enrichment of Pd(Ⅱ).Based on a LZ-2000 FI-analyzer,manifold for enrichment of Pd(Ⅱ) on the microcolumn,elution of Pd(Ⅱ) from the column with a mixture of ethylenediamine and 20 g·L-1 NaOH solution(mixed in the ratio of 1+9 by volume),and introduction of the eluate into the atomizer of AAS instrument was designed,fabricated and its operation given in detail.Waste catalyst sample was treated with HCl(5+95) solution,and the insoluble residue was collected by filtration and dissolved in aqua regia.The solution,after adjusting its acidity to pH 2,was introduced into the FI-manifold for analysis.Rate and time of sample solution introduction were 7.5 mL·min-1 and 90 s.Linear relationship between values of absorbance and concentration of Pd(Ⅱ) was kept in the range within 1.25 mg·L-1.Detection limit(3S/N) of the method was found to be 15 μg·L-1.Precision and accuracy of the method were checked by analysis of 3 samples of geological standards and platinum ores,the results obtained were in consistency with the standard or known values,with values of RSD′s(n=7) less than 2.5%.