Publications by authors named "Luiz C S Figueiredo-Filho"

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.

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Correction for 'Exploring the origins of the apparent "electrocatalytic" oxidation of kojic acid at graphene modified electrodes' by Luiz C. S. Figueiredo-Filho et al.

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Article Synopsis
  • A new electrochemical method was created to accurately measure dopamine (DA) and epinephrine (EP) in human body fluids using a modified glassy carbon electrode with nanoparticles and carbon nanotubes.
  • The technique employs square-wave voltammetry (SWV) or differential-pulse voltammetry (DPV) and achieves a notable separation of approximately 360 mV between DA and EP when they are present together.
  • The method demonstrated excellent linearity for both compounds over a specific concentration range and was effective in analyzing samples like cerebrospinal fluid, human serum, and lung fluid.
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We 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).

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We 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.

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We 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.

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