Detection of urea and rancidity of milk using inter-digitated cellulose-tin oxide hybrid composite

This work examines the possibility of utilizing cellulose-tin oxide (CTO) hybrid composite as a low cost, disposable sensing material for assessing milk quality such as, urea content and rancidity of the milk. CTO hybrid composite was prepared by adopting solution deposition technique previously reported,11 followed by fabrication of interdigitated electrode on the composite by lift-off process. Finally biosensor was constructed by immobilizing enzyme on to interdigitated CTO hybrid composite. The proposed sensor was subjected to testing with milk-urea solution in the range 0-200 mg/dl, while milk rancidity was measured by exposing pristine inter-digitated CTO hybrid composite into headspace of the milk in sealed container and changes in their electrical conductivity was recorded. Experimental results revealed that, the proposed sensor under study is suitable for detecting milk rancidity rather than milk urea.