Disposable, efficient and highly selective electrochemical sensor based on Cadmium oxide nanoparticles decorated screen-printed carbon electrode for ascorbic acid determination in fruit juices

Abstract

Here, we report a Cadmium oxide (CdO) nanoparticles modified disposable screen-printed carbon electrode (SPCE) for non-enzymatic detection of ascorbic acid (AA) with excellent stability and nano-molar detection limit. CdO nanoparticles synthesized by a simple, low-cost one-step co-precipitation method exhibits uniform crystalline nature and surface functional groups confirmed by XRD and FTIR spectroscopy. As a model analyte, AA was used to evaluate the electrocatalytic activity of CdO by cyclic voltammetry and differential pulse voltammetry (DPV) methods. The newly developed electrode, i.e., CdO nanoparticles modified SPCE shows AA oxidation peak at potential, ∼0.2 V vs. Ag/AgCl. Under optimal DPV condition, CdO-SPCE detects a wide range of concentration from 5 to 150 μM with a current sensitivity of 0.42 A M−1 cm−2 and ultra low-level detection (53.5 nM). Furthermore, the proposed sensor was highly stable and exhibited excellent selectivity towards the detection of AA in the presence of interfering electroactive agents such as urea, uric acid, glucose, citric acid, Na+ion and sucrose. For quick quality control assessment, a CdO modified SPCE (CdO-SPCE) was developed as a disposable sensor for real-time applications. A canned fruit juice (real sample) successfully analysed using CdO-SPCE exhibits a recovery value of ∼100%.