Modified electrodes with hydroquinones

Approximately 0.7-pm diameter MIP beads with hydroquinone recognition sites have been prepared using similar one-step precipitation polymerization (Table 6) [183], These beads were immobilized in an agarose gel film deposited on GCE. The resulting MIP-modified electrode has been used as a chronoamperometric chemosensor for determination of hydroquinone. The current response of the chemosensor linearly increased with the hydroquinone concentration in the range of 2-100 pM and LOD for hydroquinone was 1 pM. 

Chemically modified electrodes resulting from the attachment of quinones, phenantroline, dipyridyl complexes, and N4 complexes, from the development of polymer-coated carbon materials, and from electrodes modified by enzymes have been specifically designed for the electrocatalytic reduction of molecular oxygen (OERR). Carbon materials with immobilized hydroquinone have also been utilized to accelerate the electrochemical oxidation of molecular hydrogen. 

Fe(CN)6]3-.332 Another case to obtain quinone and hydroquinone by electrochemical oxidation of benzene with a high current efficiency, an anode modified by a bipolar ion exchange membrane, composed of a protonated poly-4-vinylpyridine layer and a perfluorocarbon sulfonic acid layer, is used. [Fe(CN)6]3 is incorporated in the inner layer (protonated poly-4-vinylpyridine) and is not contained in the solution. Release of [Fe(CN)6]3 from the inner layer is prevented by the outer layer. As a result, redox catalysts, i.e., Cr6+/Cr3+, or [Fe(CN)6]4-/ [Fe(CN)6]3 incorporated in the bipolar ion exchange membrane on the electrode surface accomplish catalysis more efficiently than if they were dissolved in the electrolyte solution.333... 

Fig. 19 (A) Background subtracted CVs on rGO/GC (al), graphite/GC (b 1) and GC electrode (cl) in 4 mM H2O2/PBS (0.1 M, pH 7), scan rate 50 mV s" (reprint with permission from ref. 78). (B) Electrochemical reduction of enzymatically produced hydroquinone (HQ) on the rGO/GC interface modified with anti-mouse IgG for the detection of mouse-IgG, revealed by interaction by anti-mouse IgG-HRP (reprint with permission from ref. 78). (C) Fabrication processes of the gold nanoparticle based graphene/chitosan bionanolabel with integrated HRP-modified carcinoembryonic antigen (HRP-anti-CEA) and measurements protocol, PB = Prussian Blue (reprint with permission from ref. 79).

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