In situ formed 1-hexyl-3-methylimidazolium hexafluorophosphate for dispersive liquid-liquid microextraction of Pd(II) prior to electrothermal AAS and spectrophotometry

摘要

1-Hexyl-3-methylimidazolium hexafluorophosphate was preparedin situ and used as extractant in dispersive liquid-liquidmicroextraction. Ultra-trace amounts of Pd(II) could be accuratelydetermined by electrothermal atomic absorption spectrometry (ETAAS)and spectrophotometry after extraction by the formed micro-droplets ofthe ionic liquid phase. 1-(2-Pyridylazo)-2-naphthol was used toproduce a hydrophobic palladium complex prior to extraction. Theeffects of concentrations of reagents, reaction and extraction times,and the other parameters were investigated and optimized. Beer's lawwas obeyed in the ranges of 0.015-0.900 and 1.50-63.0 ng mL^{-1}Pd(II) by ETAAS and spectrophotometry, respectively. Under theoptimized conditions, the limit of detection (LOD) by ETAAS was 3 ngL^{-1} with an enrichment factor of 460. The RSD percent was in therange of 1.3%-4.8% for various standard concentrations of Pd(II) inthe range of 0.050-40.0 ng mL^{-1}. Most ions did not interfere. Themethod was successfully applied to the determination of Pd(II) in somewater and alloy samples, jewels, and palladium catalysts.