An electronic device based on gold nanoparticles and tetraruthenated porphyrin as an electrochemical sensor for catechol

The aim of this study was to obtain an electrochemical device between the electrostatic interaction of the electropolymerized porphyrin {CoTPyP[RuCl 3 (dppb)] 4 }, where TPyP = 5,10,15, 20-tetrapyridilphorphyrin and dppb = 1,4-bis(diphenylphosphino)butane, and gold nanoparticles (AuNPs n− ), to be used as a voltammetric sensor to determine catechol (CC). The modified electrode, labelled as [(CoTPRu 4 ) n 8+ -BE]/AuNPs n− {where BE = bare electrode = glassy carbon electrode (GCE) or indium tin oxide (ITO)}, was made layer-by-layer. Initially, a cationic polymeric film was generated by electropolymerization of the {CoTPyP[RuCl 3 (dppb)] 4 } onto the surface of the bare electrode to produce an intermediary electrode [(CoTPRu 4 ) n 8+ -BE]. Making the final electronic device also involves coating the electrode [(CoTPRu 4 ) n 8+ -BE] using a colloidal suspension of AuNPs n− by electrostatic interaction between the species. Therefore, a bilayer labelled as [(CoTPRu 4 ) n 8+ -BE]/AuNPs n− was produced and used as an electrochemical sensor for CC determination. The electrochemical behaviour of CC was investigated using cyclic voltammetry at [(CoTPRu 4 ) n 8+ -GCE]/AuNPs n− electrode. Compared to the GCE, the [(CoTPRu 4 ) n 8+ -GCE]/AuNPs n− showed higher electrocatalytic activity towards the oxidation of CC. Under the optimized conditions, the calibration curves for CC were 21–1357 µmol l −1 with a high sensitivity of 108 µA µmol l −1  cm −2 . The detection limit was 1.4 µmol l −1 .