New Methylene Blue (NMB) Encapsulated in Mesoporous AlMCM-41 Material and Its Application for Amperometric Determination of Ascorbic Acid in Real Samples
✍ Scribed by Shabnam Sohrabnezhad; Afshin Pourahmad
- Publisher
- John Wiley and Sons
- Year
- 2007
- Tongue
- English
- Weight
- 100 KB
- Volume
- 19
- Category
- Article
- ISSN
- 1040-0397
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✦ Synopsis
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^+^ 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^−^ 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 1.0×10^−5^ to 5.0×10^−4^ M. The detection limit of the method is 1.0×10^−5^ M, low enough for trace ascorbic acid determination in various real samples.