Modification of boron-doped diamond electrodes with platinum to increase the stability and sensitivity of haemoglobin-based acrylamide sensors

Boron-doped diamond (BDD) electrodes modified with platinum and haemoglobin (Hb) have been prepared for application as stable and sensitive acrylamide biosensors. The Platinum-modified BDD (Pt-BDD) was prepared in several steps, including the wet chemical seeding of Pt particles, the electrochemical overgrowth of Pt seeds, thermal annealing at 700 °C under N₂atmosphere, as well as refresh and activation steps of Pt-BDD by cyclic voltammetry (CV). The characterization of the prepared Pt-BDD using scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS) showed that the method can deposit Pt homogenously on the BDD surface with an average particle size of around 200 nm. The Raman results showed that the treatment steps during modification did not damage the sp³carbon in the BDD structure. After modification with Hb, the modified BDD was examined for acrylamide detection. CVs of Hb-Pt-modified BDD (Hb-Pt-BDD) in 0.2 M acetate buffer saline (ABS) (pH 4.8) containing acrylamide in the concentration range of 0.01 to 1 nM showed linear responses with a detection limit of 0.0085 nM and a quantification limit of 0.026 nM. The excellent stability of the prepared Pt-BDD was confirmed as it showed the reusability of Pt-BDD by removing the Hb adduct without removing Pt on the BDD surface.