Development and Characterization of a Sol–Gel-Functionalized Glass Carbon Electrode Probe for Sensing Ultra-Trace Amounts of NH3 and NH4+ in Water

• Published in: Gels 2024-06, Vol.10 (6), p.382
• Main Authors: Alwael, H., Oubaha, M., El-Shahawi, M. S.
• Format: Article
• Language: English
• Subjects: Adsorptivity; Ammonia; Berthelot’s reaction; Carbon; Chemical elements; Chromatography; Coating; detection of NH3 and/or NH4; Electrochemical analysis; Electrodes; Fourier transforms; Glassy carbon; Metal oxides; Microscopy; modified glassy carbon electrode; Morphology; Nanoparticles; Nitrogen; Particle size; Photon correlation spectroscopy; Seawater; Sol-gel processes; sol–gel; Square waves; stripping voltammetry; Surface roughness; Thickness; Voltammetry; Water; water samples; Water sampling
• ISSN: 2310-2861; 2310-2861
• DOI: 10.3390/gels10060382

This study centers on the development and characterization of an innovative electrochemical sensing probe composed of a sensing mesoporous functional sol–gel coating integrated onto a glassy carbon electrode (sol–gel/GCE) for the detection of NH3 and/or NH4+ in water. The main interest for integrating a functional sol–gel coating onto a GCE is to increase the selective and sensing properties of the GCE probe towards NH3 and/or NH4+ ions. The structure and surface morphology of the newly developed sol–gel/GCE probe were characterized employing scanning electron microscopy (SEM), atomic force microscopy (AFM), dynamic light scattering (DLS), and Fourier-transform infrared (FTIR), while the electrochemical sensing properties were evaluated by Berthelot’s reaction, cyclic voltammetry (CV), and adsorptive square wave–anodic striping voltammetry (Ads SW–ASV). It is shown that the newly developed sol–gel coating is homogeneously deposited on the GCE with a sub-micron and uniform thickness close to 630 nm and a surface roughness of 25 nm. The sensing testing of the sol–gel/GCE probe showed limits of detection and limits of quantitation of 1.7 and 5.56 nM of NH4+, respectively, as well as a probe sensitivity of 5.74 × 10−1 μA/μM cm−2. The developed probe was fruitfully validated for the selective detection of NH3/NH4+ in fresh and sea water samples. Computed Student texp (0.45–1.25) and Fexp (1.69–1.78) (n = 5) tests were less than the theoretical ttab (2.78) and Ftab (6.39) at 95% probability.