Digital Colorimetric Analysis of Aqueous and Aqueous–Organic Systems Using Polyvinyl Alcohol–Magnetite Hydrophilic Composite Films

The application of composite films consisting of crosslinked polyvinyl alcohol and magnetite as sensitive elements in the determination of the composition of aqueous solutions by digital colorimetry is described. A novel approach to fabricating composite materials of the composition hydrophilic polymer–magnetite is proposed; it involves the precipitation of Fe3O4 particles in ammonia vapors. The sensor films produced by this method were employed for determining the volume fraction of alcohol in products characterized by high alcohol content. The limit of detection for ethanol was determined at 63 vol %, while for isopropanol, it 24 vol %. The efficacy of the proposed sensor materials was assessed through in an analysis of liquid hand sanitizers.