Supercritical fluid-assisted fabrication of CuxOSAS-based electrochemical sensor for cysteine detection with enhanced sensitivity and reduced oxidation potential

Abstract

This work demonstrates a rapid and effective strategy to make a cysteine detection system with higher sensitivity and lower detection limit using an eco-friendly supercritical antisolvent (SAS) technology. Copper salt particles were prepared via SAS and transformed into copper(I/II) oxide (CuxOSAS) upon calcination at 400℃. The resulting calcinated product exhibited a significantly reduced particle size and the presence of mixed valence states. The fabricated CuxOSAS cysteine detection system demonstrated excellent performance, with a cyclic voltammetry (CV) curve displaying a low oxidative overpotential (∼0.1 V vs. Ag/AgCl). The linear detection range was 0.001 μM to 0.25 μM and 0.25 μM to 1000 μM, respectively, with corresponding sensitivity of 2447.1 μA·cm−2·μM−1 and 0.3714 μA·cm−2·μM−1, respectively. In conclusion, the SAS-prepared CuxOSAS hold great prospective for electro-sensing and biomolecular catalysis applications.