Flavin mononucleotide-exfoliated graphene flakes as electrodes for the electrochemical determination of uric acid in the presence of ascorbic acid

Abstract

Gold interdigitated microelectrodes (Au-IDA) modified with either graphene flakes exfoliated using flavin mononucleotide (FMN) (Gr-FMN) or graphene flakes and platinum nanoparticles (Pt-Gr-FMN) have been studied in the oxidation of uric acid (UA). An electrochemical method for the detection and quantification of UA in phosphate buffer solution at physiological pH (PBS, 0.25 M, pH 7) in the absence and presence of ascorbic acid (AA) has been studied by cyclic voltammetry.The quantification of UA was investigated by cyclic voltammetry, presenting an oxidation peak at 0.99 V with both modified electrodes. Linearity range of 60-578 µM and 60-345 µM has been found for Gr-FMN/Au-IDA and Pt-Gr-FMN/Au-IDA electrodes, respectively. Limits of detection of 18 µM were obtained for both electrodes, and the repeatability was studied at 177 µM providing 4% and 8% for Gr-FMN/Au-IDA and Pt-Gr-FMN/Au-IDA, respectively. AA interference has been studied by cyclic voltammetry, showing two clearly separated oxidation peaks, at 0.99 V for UA oxidation and at 0.74 V for Gr-FMN/Au-IDA and 0.70 V for Pt-Gr-FMN/Au-IDA for AA oxidation. Linearity range has been studied in presence of 250 µM AA obtaining a working range of 60-578 µM for Gr-FMN/Au-IDA electrode and of 60-288 µM with Pt-Gr-FMN/Au-IDA electrode.Limits of detection remain at 18 µM for both electrodes and the repeatability was studied at 177 µM providing 8% and 14% for Gr-FMN/Au-IDA and Pt-Gr-FMN/Au-IDA electrodes respectively.

Evaluation of herringbone carbon nanotubes-modified electrodes for the simultaneous determination of ascorbic acid and uric acid

“…electrochemical sensors [9][10][11][12][13][14]. Specifically, carbon nanotubes (CNTs) are excellent electrode materials due to their physical and chemical properties, and they have received enormous attention for the study of electrochemical sensors [15][16][17][18][19][20].…”

Electrocatalytic Determination of Uric Acid with the Poly(Tartrazine)-Modified Pencil Graphite Electrode in Human Serum and Artificial Urine

“…Uric acid (2,6,8-trihydroxypurine, UA) is the end product of purine metabolism in humans, formed by the oxidation of xanthine and hypoxanthine, but is more toxic than these and is omnipresent in urine and blood . The normal range of UA in healthy individuals varies from 1.4 to 4.4 mM in urine and from 240 to 520 μM in blood . UA is a natural antioxidant and is able to eliminate free radicals and singlet oxygen.…”

“…3 [Fe(CN) 6 ], 1 mM of K 4 [Fe(CN) 6 ], and 0.1 M of KCl) with a step amplitude of 3 mV and a proper scan rate. The solution consisting of 0.05 M pH 7.5 PBS with or without real samples (i.e., human serum and artificial urine) was set to 10 mL with ultrapure water and deaerated with argon for 3 min.…”

Stabilization of aqueous graphene dispersions utilizing a biocompatible dispersant: a molecular dynamics study

“…35 This benign and readily available biocompatible dispersant outperformed the other biomolecules in the preparation of stabilized graphene in aqueous solution, and showed great potential for biomedical applications. [36][37][38][39][40] To the best of our knowledge, the role of the FMNS dispersant for the stabilization of graphene flakes have not been fully understood until now.…”