New optical sensor based on the immobilization of a triazene ligand in PVC membrane for Hg(II) ion

This paper describes the development and creation of a new sensitive optical sensor that is quite selective to Hg(II) ions in aqueous solution. The sensing element, the newly synthesized methyl 2-[3-(3-methylphenyl)-2-tri­azen-1-yl]benzoate, incorporated into a plasticized poly(vinyl chloride) mem­brane, is able to determine Hg(II) ion with a high selectivity over a wide dyn­amic range from 5.0–115.1 μg L-1 at pH 7.5 with a lower detection limit of 0.67 µg L-1. The response of the optode membrane to Hg(II) was fully rever­sible and revealed a very good selectivity towards Hg(II) ion from a wide var­iety of other metal ions in solution. The overall performance characteristics of the sensor were evaluated and good reversibility, wide dynamic range, long life span, long-term response stability and high reproducibility were found. The proposed optical sensor gives proper results in applications including direct determination of the Hg(II) ion in real environmental samples.