Fabrication of iridium-gold nanocomposite for the detection of selective serotonin reuptake inhibitors

A comprehensive study of the development of a novel electrochemical sensor based on iridium-gold nanocomposite (IrAuNPs) modified electrodes for the detection of antide­pres­sants, paroxetine (PRX) and citalopram (CIT) was conducted. The sensing platform, based on a glassy carbon electrode, was modified by drop-casting IrAuNPs, which allowed for enhanced conductivity. IrAuNPs, along with their counterparts iridium nanoparticles (IrNPs) and gold nanoparticles (AuNPs), were synthesized from coffee waste extract (CWE) via complete green chemistry. The physicochemical properties of synthesized nanomaterials were characterized using ultraviolet-visible spectroscopy, dynamic light scattering, high-resolution transmission electron microscopy, Fourier-transform infrared spectroscopy, cyclic voltammetry and square wave voltammetry. Results showed that the CWE could reduce the respective metallic salts to form mostly near-spherical to spherical IrAuNPs, IrNPs and AuNPs with core sizes ranging from 2.02 nm to 13.27 nm. The electrochemical sensor could determine PRX and CIT in the concentration ranges of 20 to 200 nM and 1 to 10 µM, with detection limits of 0.072 nM and 0.085 µM, respectively. The sensor showed a recovery of 86 to 115.1 %. The proposed sensor demonstrated good precision and accuracy, with excellent sensitivity and selectivity for drug identification in a rapid analysis time, which is crucial for applications in biological matrices.