New Methylene Blue (NMB) Encapsulated in Mesoporous AlMCM‐41 Material and Its Application for Amperometric Determination of Ascorbic Acid in Real Samples

Abstract

New methylene blue (NMB) dye incorporated into AlMCM-41 surfactant-free and hybrid surfactant-AlMCM-41 mesophase. UV-vis evidence shows that new methylene blue dye protonated in both cases of zeolites. New methylene blue is electroactive in zeolites and their electrochemical activity has been studied by cyclic voltammetry and compared to that of NMB in aqueous solutions. New methylene blue molecules are not released to the solution during CV measurements and are accessible to H 3 O þ ions. The presence of surfactant affects the kinetics of the redox process through proton ions diffusion. The midpoint potentials (E m ) values show that new methylene blue dye incorporated into AlMCM-41 can be reduced easily with respect to solution new methylene blue. New methylene blue interacting with surfactant polar heads and residual Br À ions as a results, it shows a couple of peaks in high potential with respect to new methylene blue solution. The electrode made with methylene blue-AlMCM-41 without surfactant was used for the mediated oxidation of ascorbic acid. The anodic peak current observed in cyclic voltammetry was linearly dependent on the ascorbic acid concentration. The calibration plot was linear over the ascorbic acid concentration range 1.0 Â 10 À5 to 5.0 Â 10 À4 M. The detection limit of the method is 1.0 Â 10 À5 M, low enough for trace ascorbic acid determination in various real samples.

Simultaneous Detection of Ascorbic Acid and Hydrogen Peroxide by Flow‐Injection Analysis with a Thin Layer Dual‐Electrode Detector

“…They are mostly based on titrimetric [5], chromatographic [6,7], spectrometric [6,[8][9][10], enzymatic [11][12][13] and electroanalytical [6,12,[14][15][16][17][18] approaches. Almost all of these methods suffer from interference from several species [19], among which hydrogen peroxide (H 2 O 2 ) is by far the worst.…”

Redox Reactivity of Methylene Blue Bound in Pores of UMCM-1 Metal-Organic Frameworks

“…Furthermore, some MOFs have been demonstrated to effectively photocatalyse MB degradation, presumably via initial absorption [16]. In a recent zeolitebased report [17], a structurally related methylene blue dye has been shown to bind into a mesoporous host, whilst maintaining its electrochemical and electrocatalytic activity for ascorbic acid electroanalysis. Work on electrochemical applications of methylene blue intercalated into porous α-Zr(HPO 4 ) 2 host has been reported [18,19].…”