Development and application of electrochemical sensor of boron-doped diamond (BDD) modified by drop casting with tin hexacyanoferrate

• Published in: Journal of solid state electrochemistry 2020-08, Vol.24 (8), p.1769-1779
• Main Authors: Guimaraes, Giulia A. A., Lacerda, Janiny N., Xing, Yutao, Ponzio, Eduardo A., Pacheco, Wagner F., Semaan, Felipe S., Dornellas, Rafael M.
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Atomic force microscopy; Boron; Characterization and Evaluation of Materials; Chemical bonds; Chemical composition; Chemical sensors; Chemistry; Chemistry and Materials Science; Condensed Matter Physics; Diamonds; Dopamine; Electrical measurement; Electrochemical analysis; Electrochemical impedance spectroscopy; Electrochemistry; Electrodes; Electron transfer; Energy Storage; Frequency analysis; Mathematical analysis; Microscopy; Original Paper; Physical Chemistry; Raman spectroscopy; Saliva; Spectrum analysis
• ISSN: 1432-8488; 1433-0768
• DOI: 10.1007/s10008-020-04558-6

This work presents the development and characterization of an electrochemical sensor of tin hexacyanoferrate (SnHCF), produced from the modification by drop casting of the boron-doped diamond electrode (BDD), and its subsequent evaluation in the determination of dopamine (DP) in a synthetic saliva sample. The sensors, BDD-SnHCF and unmodified BDD, were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), and electrochemical impedance spectroscopy, where the BDD-SnHCF presented higher roughness and lower resistance to electronic transfer. Raman spectroscopy and energy-dispersive X-ray spectroscopy (EDS) were used to confirm the chemical composition and bonding of the SnHCF film. The electroactive area and the heterogeneous electron transfer rate constant (k 0 ) presented higher values for BDD-SnHCF. Analytical curves were constructed, by batch injection analysis (BIA) with amperometric detection (BIA-AMP), and the slope obtained for BDD-SnHCF was significantly higher when compared with unmodified BDD. The detection limit for BDD-SnHCF (0.21 μmol L −1 ) presented a value sevenfold lower than unmodified BDD and good analytical frequency (72 h −1 ) obtained for the modified electrode. The determination of DP in saliva, as a proof-of-concept, achieved an excellent accuracy, reported by a recovery of (90% ± 8) in the sample. The results showed that SnHCF is an interesting alternative for the BDD drop casting modification, presenting a significant improvement in the electrochemical characteristics and analytical performance of DP in the determination by BIA-AMP compared with unmodified BDD.