Paper-Based Biosensor for Rapid Cr(VI) Detection in Water

This study develops a low-cost paper-based electrochemical biosensor for detecting toxic hexavalent chromium [Cr(VI)] in water. Glucose oxidase (GOx) was immobilized on filter paper using chitosan, achieving approximately 90% enzyme entrapment efficiency and nearly 97% stability after one week at 4 °C. The biosensor, integrated with a screen-printed carbon electrode, provided a linear detection range of 0.05–1 ppm with a limit of detection of 0.05 ppm and 5.6% RSD. The results demonstrate the potential of paper-based biosensors for simple and portable heavy-metal monitoring.