A novel optode sensor for the determination of palladium(II) in water and a hydrogenation catalyst

A novel optical sensor was established to determine palladium(II) based on the immobilization of 1-(2-pyridylazo)-2-naphthol (PAN) on a triace- tylcellulose membrane. Palladium ions react with the immobilized PAN and cause a decrease in the absorbance of the membrane at 469 nm. The response time of the optode was 8-10 min depending on the concentration of Pd(II) ions. This sensing phase had a dynamic linear range of 0.10-12.0 µg ml-1 palladium ions with a limit of detection of 65 ng ml-1. The sensor can readily be regene- rated using an ethylenediamine solution. The sensor could be fully regenerated, and the color change was fully reversible. The method was successfully applied for the determination of Pd(II) in synthetic aqueous solutions and in a hydro- genation catalyst sample.