In this work, a biosensor using a glassy carbon electrode modified with gold nanoparticles (AuNPs) and tyrosinase (Tyr) within a dihexadecylphosphate film is proposed. Cystamine and glutaraldehyde crosslinking agents were used as a support for Tyr immobilization. The proposed biosensor was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and cyclic voltammetry in the presence of catechol.
View Article and Find Full Text PDFCorrection for 'Exploring the origins of the apparent "electrocatalytic" oxidation of kojic acid at graphene modified electrodes' by Luiz C. S. Figueiredo-Filho et al.
View Article and Find Full Text PDFWe report the fabrication, characterisation (SEM, TEM, XPS and Raman spectroscopy) and electrochemical implementation of a graphene paste electrode. The paste electrodes utilised are constructed by simply mixing graphene with mineral oil (which acts as a binder) prior to loading the resultant paste into a piston-driven polymeric-tubing electrode-shell, where this electrode configuration allows for rapid renewal of the electrode surface. The fabricated paste electrode is electrochemically characterised using both inner-sphere and outer-sphere redox probes, namely potassium ferrocyanide(ii), hexaammine-ruthenium(iii) chloride and hexachloroiridate(iii), in addition to the biologically relevant and electroactive analytes, l-ascorbic acid (AA) and uric acid (UA).
View Article and Find Full Text PDFWe explore the recent reports that the use of graphene modified electrodes gives rise to the electrocatalytic oxidation of kojic acid. It is demonstrated that large quantifiable voltammetric signatures are observed on bare/unmodified graphitic electrodes, which are shown to be analytically useful and superior to those observed at graphene modified alternatives. This work is of importance as it shows that control experiments are critical and must be undertaken before "electrocatalysis" is conferred when investigating graphene in electrochemistry.
View Article and Find Full Text PDFWe present the electroanalytical sensing of atropine using disposable and economic screen printed graphite sensors. The electroanalytical determination of atropine is found to be possible over the concentration range of 5 μM to 50 μM with a detection limit of 3.9 μM (based on 3-sigma) found to be possible.
View Article and Find Full Text PDF