Design and fabrication of nano ceria based paper sensor for determination of dopamine by colorimetric method

Nano ceria or cerium oxide nanoparticles have a unique structure, unusual redox and catalytic properties. These characteristics vary with the size, shape, charge and surface coating of nano structures [1]. In this work cerium oxide nanoparticles were synthesized by a cloudy method and used to fabricate nano ceria based paper sensor for one of the most important neurotransmitters-dopamine detection at biological samples. This sensor is based on the oxidase-like activity of nano ceria particles. The practical conditions were optimized and characterized with respect to particle loading, pH, response time, paper type ,paper size ,detection limit, linear concentration range and sensitivity[2].The interaction between dopamine and the redox active nano ceria was studied using spectrophotometric and surface characterization methods. The results indicated strong attachment of dopamine to the nanoparticle surface through oxidation followed by chemisorption of the oxidative product with formation of a charge transfer complex [3]. The prepared nano ceria based paper sensor exhibited not only high selectivity toward dopamine in comparison to other interferents, but also a wide linear range over dopamine concentration from 100-1000 µM and 1000-5000 µM, with a coefficient of determination (R2) of 0.997-0.9819. Moreover, the new nano ceria based paper sensor was successfully applied for dopamine detection in dopamine hydrochloride injection and human urine, serum ,plasma sample with satisfactory quantitative recoveries of 99%,100%,105% and showed great potential in clinical diagnosis[4]. This simple detection tool possess many unique advantages, including inexpensive, low-volume, portable, disposable, and easy-to- fabricate and use. This new nano ceria based paper sensor can be stored for at least 30 days at room temperature while maintaining the same analytical performance.