A recyclable polymeric film for the consecutive colorimetric detection of cysteine and mercury ions in the aqueous solution

Aldehyde-functionalized azo-containing polymer was synthesized and characterized. Consecutive sensing of cysteine and mercury (II) ions was checked in water with high selectivity and sensitivity. After immobilizing the polymer on the surface, the successive colorimetric detection of cysteine and mercury (II) ions was repeatable over several cycles, demonstrating the whole system to be reversible, and this polymeric film can be reused.