Resumo

SCARPETTA, Laura et al. Determination of hydroquinone using a glassy carbon electrode modified with chitosan, multi-wall carbon nano-tubes and ionic liquid. Possible use as sensor. Rev. colomb. cienc. quim. farm. [online]. 2015, vol.44, n.3, pp.311-321. ISSN 0034-7418.  https://doi.org/10.15446/rcciquifa.v44n3.56283.

Property of the electroactive hydroquinone (HQ) was studied on a glassy carbon electrode modified chitosan, multi wall carbon nanotubes (Ch-MWCNT-GCE). HQ is deposited at a controlled potential to the electrode surface and oxidation of HQ is measured by square wave voltammetry (SWV). An oxidation current to 0.39 V and a reduction current to 0.21 V with a 0.18 ΔV indicating a reversible process were observed. An increase in the flow of oxidation and reduction of almost 50% was observed when the Ch-MWCNT-GCE was coated with ionic liquid (LI). The electrode was characterized by cyclic voltammetry (CV) in the presence and without the presence of different ionic liquids with different anion being the most optimal ionic liquid (LI) 1-butyl-3-methyllimidazolio hexafluorophosphate (BMIMPF₆). Experimental variables such as pH, adsorption time (TADs) and adsorption potential (E_ads), as well as potential interference, were studied. Under optimal conditions (pH 3.0; t_acc 60s; E_acc 0.10 V) the peak current is proportional to the concentration of HQ between 4.20 * 10^-6 and 30.0 * 10^-5 mol L^-1 with a detection limit of 2.45 * 10^-7 mol L^-1. The relative standard deviation for a solution containing 1.0 * 10^-4 mol L^-1 HQ was 1.5% for seven equal measures. The method was validated with a water sample doped with HQ.

Palavras-chave : Hydroquinone; adsorption voltammetry; modified electrode; ionic liquid.

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