Application of Complex Forming Impregnated Polyvinyl Alcohol for the Determination of Carbohydrates by Optical Micrometry

A possibility of determining concentrations of water-soluble carbohydrates by optical micrometry using granules of polyvinyl alcohol (PVA) impregnated with sodium tetraborate is shown. The influence of the acidity on the analytical signal is studied. The optimum pH range for the determination of the glucose concentration in the presence of sucrose is 8.5–10.0. A sensitive polymer granule needs about 30 min to achieve an equilibrium volume, and a change in the volume is reversible. The calibration plot for the determination of the glucose concentration in the range from 0 to 40 mmol/dm3 is constructed. The impregnation of the PVA granules with sodium tetraborate is shown to decrease the detectability threshold to 6.9 mmol/dm3 and to increase the selectivity, which can be varied by changing the pH of the solution.