Transparent Membrane of Polyelectrolyte Complex Doped with 2,6-Dichlorophenol-Indophenol as an Optical Sensor for Colorimetric Measurements of Ascorbic acid

Abstract

An optical chemical sensor based on a transparent membrane of polyelectrolyte complex (PEC), composed of alginate-chitosan membrane and 2,6-dichlorophenol-indophenol (2,6-DCPIP), coated on transparent mica was coupled with UV-Vis spectrophotometry and used for colorimetric measurements of ascorbic acid (AA). The transparent membranes of PEC were characterized using scanning electron microscopy (SEM) technique. The experimental parameters of the biosensor were optimized. Here, the optical chemical sensor showed maximum response at wavelength of 545 nm, with the optimum pH at 3. The calibration curve had a dynamic working range at 0.0 to 5.0 mM of AA with a limit of detection (LOD) of 0.13 mM AA. The membrane sensor has a long life time in the defined condition (4 o C). The developed optical chemical sensor correlated well with the standard method, HPLC for the determination of Ascorbic acid concentration in real samples.