Design of Electrochemically Reduced Graphene Oxide/Titanium Disulfide Nanocomposite Sensor for Selective Determination of Ascorbic Acid

Synthesizing conductive nanocomposites (NCs) for realizing an ultrasensitive biosensor is a prevalent technological thrust. Herein, a simple and unusual design of a sensing platform is documented using electrochemically reduced graphene oxide/titanium disulfide nanocomposite (erGO/TiS2 NC) for detection of ascorbic acid (AA): a significant neurobiological molecule. The NC is designed via sonolysis of a solution comprising ex situ-synthesized GO and TiS2 and subsequently electrochemically reduced for fabricating the sensing interface. Advanced analytical studies are carried out to support the construction of the erGO/TiS2//glassy carbon electrode (GCE). Under the optimal measuring conditions, the sensor offers two linear responses within (i) 0.1 → 1 μM, a limit of detection (LoD) of 30.2 nM (S/N = 3) and a sensitivity of 0.34 μA·μM–1·cm–2, and (ii) 1 → 400 μM, a LoD of 91.4 nM and a sensitivity of 0.11 μA·μM–1·cm–2 for AA. Moreover, the sensor demonstrates high selectivity toward AA over other bioanalytes except for tiny anodic responses of cysteine (7.5%) and dopamine (8.9%). Finally, the practicability of the proposed sensor has been tested for AA in pharmaceutical and human urine samples and validated by high-performance liquid chromatography-mass spectrometry (HPLC-MS). Overall, the sensor demonstrates satisfactory reliability for recovery of AA and can be considered for the diagnosis of clinical samples.