Anthropogenic industrialization related activities contribute to rising concentrations of heavy metal in the environment. This unprecedented deterioration of water quality by industrial effluents raises severe global health concern to both humanity and the ecosystem. Chromium, the 21^st most abundant element on the earth’s crust, is extensively used in steel manufacturing, leather tanning, electroplating, paint and alloy manufacturing industries. The effluents released pollute water with Cr(III); classified as a group III carcinogen causing genotoxicity to flora and fauna. Hence water quality monitoring by detecting heavy metal concentration in tap water, canned liquid food items, etc will be of immense application if the sensor is affordable and equipped with simple user interface. Conventional methods like ICP-MS and AAS demand time, expense and complex equipments which are beyond the scope of daily use.

This work reports detection of Cr(III) employing Field Effect Transistor with Ion Selective Membrane on the gate electrode.The gate metal is extended and terminates in a two sensing electrode configuration modified with Poly Vinyl Chloride based sensing material.It is composed of an ionophore which binds with target analyte; consequently leading to a change in the transistor drain current. High sensitivity, selectivity and fast response time were observed in the pH range 3- 5 beyond which Cr forms hydroxyl complexes.The effective voltage at gate dielectric is a function of the concentration of Cr(III) ions in the test solution dropped on the sensing membrane. The device exhibits increasing trend of current gain with increase in concentration of the target ion as depicted in the plot. Hence, our simple novel biosensor can be calibrated to realize a cost effective, portable device to measure concentration of Cr(III) in real time drinking water quality monitoring or be integrated into food processing systems or even in medical diagnostics.