Poly-L-Arginine-Modified Boron-Doped Diamond and Glassy Carbon Electrodes for Terbutaline Sulfate Detection

This work describes the electro polymerization of a poly-L-arginine film onto boron-doped diamond (BDD) electrode and glassy carbon electrode (GCE) surfaces. The morphological and electrochemical properties of the modified electrodes were studied by atomic force microscopy and electrochemical methods, and their potential for terbutaline sulfate (TBS) detection was determined by voltammetry and chronoamperometry techniques. Our results demonstrate that the electrochemical surface area of both uncoated-bare electrodes (GCE e BDD) did not have significant differences in performance. However, higher current observed for TBS at poly-arginine/GCE is probably due to the higher surface coverage poly-arginine at GCE than BDD. It was concluded that for the systems under study, the poly-L-arginine/GCE was more suitable for TBS detection than that by the poly-L-arginine/BDD electrode, due to the more continuous and thicker poly-L-arginine film formed on the GCE, as revealed by the microscopy images. The TBS sensitivity and detection limit of the poly-L-arginine/GCE were determined to be 0.9 ±0.1 μA μmol⁻¹L cm⁻² and 0.10 μmol L⁻¹, respectively, by chronoamperometry. Furthermore, the abilities of the electrodes to detect other β-agonists, namely clenbuterol and salbutamol, were studied by performing electrochemical experiments in the presence of these analytes. The results suggest that this film is a promising material for TBS detection due to high-surface-area electrochemical electrodes, and for the electrostatically-controlled thin film interference filter.