Improved Voltammetric Discrimination of Acetaminophen and Uric Acid in Urine Using CoO Biochar Nanocomposite

Overuse of acetaminophen (APAP) has become a severe societal burden in recent years. The rapid and reliable detection of urinal APAP concentration can offer certain guidance for better management of APAP usage. This study explored the electrochemical sensing application of a novel electrocatalyst prepared from the biomass of Elaeagnus Angustifolia gum. The biomass was first activated by ferric chloride to form a porous biomass carbon material (FBC). Then synthesized cobalt oxide cracked nanoplate by alkali precipitation and calcination approach were hybridized onto the biomass carbon via facile sonication process. The electrocatalyst of CoO-FBC was characterized by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), element mapping, transmission electron microscopy (TEM) and high resolution TEM, X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD), thermo gravimetric analysis (TGA), Raman spectroscopy, and nitrogen adsorption/desorption analysis. CoO-FBC modified glassy carbon electrode (CoO-FBC/GCE) was characterized by various electrochemical methods including cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). CoO-FBC/GCE sensor was used to measure APAP in pH 7.0, 0.1 M phosphate buffered saline (PBS) with two linear sensing range from 1 μM to 10 μM and 10 μM to 100 μM, sensitivity of 25.89 μA μM-1 cm-2 and 10.04 μA μM-1 cm-2, and limit of detection of 0.46 μM. The unavoidable inteference in measuring APAP is the inherent uric acid in urine. Uric acid and APAP exhibited adjacent and sometimes unseparable voltametric peak. This CoO-FBC/GCE sensor is capable to distinguish APAP from uric acid and to measure APAP in human urine sample with good recovery. This CoO-FBC/GCE sensor has promising application in clinical diagnosis and environmental detection.