Sensing Granular Material Based on an Impregnated Cross-Linked Polyvinyl Alcohol–Magnetite Composite to Determine Carbohydrates Using Optical Micrometry

The process of obtaining a cross-linked polyvinyl alcohol–magnetite composite impregnated with sodium tetraborate solution is considered and its application as a sensitive element to determine carbohydrates in aqueous solutions using optical micrometry is explored. The IR spectroscopy method is used to confirm the chemical structure of the studied polymer. Magnetization curves are used to calculate the particle content of Fe3O4 in polyvinyl alcohol (PVA) pellets. It is proved that magnetite introduced into the pellets at pH 6.8 narrows the concentration range of carbohydrates determined and reduces the sensitivity of the PVA matrix to the carbohydrates. However, at pH 8.6, the presence of Fe3O4 particles in the pellets does not increase the limit of detection of glucose and fructose (7.9 mmol/dm3) but reduces the relative standard deviations to 3 wt %. The sensor pellets having the optimum magnetite content (1.54%) are validated to detect the total carbohydrate content in natural syrup samples having high fructose concentration using an optical micrometry. The results agree well with those reported by syrup manufacturers.