An optode for determination of mercury based on Nafion-diphenylcarbazone thin film in a flow-stream

An optode for determination Hg(II) ion has been developed using diphenylcar bazone (DC) immobilised in a Nafion(R) film. The film is transparent, homog eneous and mechanically strong, and changes in colour from orange to violet in the presence of Hg(II). The optode film can be generated readily using an acid solution. The optode has been incorporated into flow system, and ch aracterised for determination of Hg(II) in the concentration range 0.5-50 m uM with detection limit 0.2 muM (or 40 mug L-1). The response time of the o ptode film was within 8-15 min to reach 90% of the final signal and depends on the concentration of Hg(II) ions. Interferences from other ions have al so been investigated.