Ternary ion-association complex based ion imprinted polymers (IIPs) for trace determination of palladium(II) in environmental samples

A new ion imprinted polymer (IIP) material was synthesized by co-polymerization of palladium-iodide-vinyl pyridinium/palladium-thiocyanate-vinyl pyridinium ion ternary ion-association complex taken in methanol/DMSO with 2-hydroxyethyl methacrylate (functional monomer) and ethylene glycol dimethacrylate (crosslinking monomer) in the presence of 2,2′-azobisisobutryonitrile (initiator). The imprinted anionic species PdI₄]²⁻ or Pd(SCN)₄]²⁻ were removed by leaching the dried and powdered materials particles for 18 h with 6 M HCl to obtain leached IIP particles. Non-imprinted/control polymers were also prepared in a similar fashion without the template. Various parameters that influence the percent extraction of palladium, viz. concentration of KI or KSCN, pH, weight of polymer particles, preconcentration and elution times, aqueous phase volume, etc., were systematically studied for both the systems, i.e., in batch as well as flow injection modes. As the on-line flow injection-flame atomic absorption spectrometric (FI-FAAS) allow offer higher enrichment factor, better precision and can analyze more samples for a given time, compared to batch method, this procedure is preferred for the analysis of palladium present in the street/fan blade dust samples collected from busy cities of India and the values obtained were compared with the standard ICPMS values.