Potentiometric Nonenzymatic Ascorbic Acid Sensor for Static and Dynamic Measurements

Abstract

We fabricated a potentiometric nonenzymatic ascorbic acid (AA) sensor. The main sensing materials are molybdenum trioxide (MoO3) film and copper oxide nanoparticles (CuO NPs). Basic sensors and sensing materials were fabricated by the screen printing technique, the radio frequency sputtering system, and the green synthesis method. The average sensitivity, linearity, and interference effects of the AA sensor under static measurements were examined. In order to simulate dynamic measurements, we performed experiments by the microfluidic system and analyzed the best sensing characteristic at low flow rates (1.4– <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$7.0~\mu \text{L}$ </tex-math></inline-formula> /min) and high flow rates (10– <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$50~\mu \text{L}$ </tex-math></inline-formula> /min). The best average sensitivities under static and dynamic measurements are 35.26 and 61.11 mV/decade, respectively. Ultimately, the AA sensor achieves better stability and accuracy with the help of a unity-gain frequency and low power consumption instrumentation amplifier (UGFPCIA). This study shows that the AA sensor can possibly achieve excellent sensing properties even without the help of enzyme and a conventional commercial chip (LT1167).