All Solid State Graphene Based Potentiometric Sensors for Monitoring of Mercury Ions in Waste Water Samples

In this work, all-solid-state potentiometric PVC membrane sensor was introduced for fast and simple monitoring of mercury ions in waste water samples. The all solid sate electrode is made based on a conductive composite of graphite, reduced graphene oxide, epoxy resin on a copper wire. A thin layer PVC membrane is then coated on the surface of the new conducting transducer. PVC membrane is composed of 30% PVC, 62% NPOE as plasticizer, 3% ionic liquid, and 5% Hg2+ ion imprinted polymer (IIP). The sensing element of the sensor is an artificial host which is imprinted by vinyl pyridine and a suitable cross-linker. The sensor shows a Nernstian response of 29.4±0.3 mV/decade. Dynamic linear range of the sensor is 1.0×10-8-1.0×10-3 mol/L of the mercury concentration and detection limit of 3.2×10-9 mol/L. The interference of different ionic species with the response of the electrode shows a good selectivity of the proposed sensor. The proposed sensor is successfully applied in determination of mercury ions in some waste water samples.