Overoxidized poly(3,4-ethylenedioxythiophene)–gold nanoparticles–graphene-modified electrode for the simultaneous detection of dopamine and uric acid in the presence of ascorbic acid

Abstract

An innovative, ternary nanocomposite composed of overoxidized poly(3,4-ethylenedioxythiophene) (OPEDOT), gold nanoparticles (AuNPs), and electrochemically reduced graphene oxide (ERGO) was prepared on a glassy carbon electrode (GCE) (OPEDOT–AuNPs–ERGO/GCE) through homogeneous chemical reactions and heterogeneous electrochemical methods. The morphology, composition, and structure of this nanocomposite were characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The electrochemical properties of the OPEDOT–AuNPs–ERGO/GCE were investigated by cyclic voltammetry using potassium ferricyanide and hexaammineruthenium(III) chloride redox probe systems. This modified electrode shows excellent electro-catalytic activity for dopamine (DA) and uric acid (UA) under physiological pH conditions, but inhibits the oxidation of ascorbic acid (AA). Linear voltammetric responses were obtained when DA concentrations of approximately 4.0–100 μM and UA concentrations of approximately 20–100 μM were used. The detection limits (S/N=3) for DA and UA were 1.0 and 5.0 μM, respectively, under physiological conditions and in the presence of 1.0 mM of AA. This developed method was applied to the simultaneous detection of DA and UA in human urine, where satisfactory recoveries from 96.7% to 105.0% were observed. This work demonstrates that the developed OPEDOT–AuNPs–ERGO ternary nanocomposite, with its excellent ion-selectivity and electro-catalytic activity, is a promising candidate for the simultaneous detection of DA and UA in the presence of AA in physiological and pathological studies.

Current developments of bioanalytical sample preparation techniques in pharmaceuticals

“…The MEPS cartridge is packed with sorbent materials to provide suitability in operation. Several sorbents used in MEPS are cation exchanger, graphene oxide [ 179 ], reduced graphene oxide [ 180 ], organic monoliths, carbon NPs, ISs, and MIPs. Recently, MEPS has been applied in the determination of zonisamide, meropenem, levofloxacin, statins, and fluoxetine in plasma.…”

Melamine-Based Nanocomposites for Selective Dopamine and Uric Acid Sensing

“…8,9 Therefore, it is still a challenge to develop a special electrode modification material for selective detection of DA and UA. 10,11 In recent years, electropolymerization of melamine and its mechanism have been reported. 12 Considering the abundant nitrogen element and amino groups, electroactive poly-(melamine) (PMEL) and its composites are often used to construct the electrochemical sensors for different targets, such as the pH, Klonopin, 13 nitrite, and tartrazine.…”

Electroactive and SERS-Active Ag@Cu2O NP-Programed Aptasensor for Dual-Mode Detection of Tetrodotoxin

“…The design of electroactive and SERS-active detection nanoprobes with strong and stable electrochemical/SERS double signals is the basis for the dual-mode detection assays. The commonly used electroactive probes include organic compounds (methylene blue, ferrocene, and potassium ferricyanide), − quantum dots (PbSe, CdSe, and CdTe), − metal nanoparticles (NPs) (Ag NPs, Ru NPs, and Pt NPs), ,, and metal oxides (Cu 2 O NPs and CdO NPs). , Organic compounds generally need to be loaded on the surface of carriers, in order to obtain strong electrochemical redox signals. − Quantum dots generally need to be dissolved in strong acid or strong base electrolyte solution, in order to obtain strong electrochemical activity. − In particular, metal NPs and metal oxides not only exhibit strong electrochemical activity under mild neutral conditions but also exhibit tunable electrochemical signals by changing the morphology and sizes. Alternatively, Ag NPs and Cu 2 O NPs were found to display tunable electrooxidation signals at around 0.17 and −0.13 V .…”