Determination of saturation concentrations and refractive indices of pure sucrose solutions by means of the immersion refractometer

By means of an immersion refractometer the authors carried out measurements for determining saturation concentrations and refractive indices of pure sucrose solutions in the temperature range between 20 and 90° C and in the concentration range between 1.25 and 4.15 kg of sucrose per kg of water or between 0.575 and 0.805 kg of sucrose per kg of solution.

Scale readings obtained as measuring results are plotted against the concentration of solution for different temperatures. By means of scale readings for saturated solutions which also have been recorded, saturation concentrations have been determined for which equations are given in the concentration systems used.

A comparison with the values found by Charles shows a good conformity in the lower temperature range up to about 500 c. At higher temperatures a maximum deviation of 0.10 °/o occurs. Therefore the values of Charles are certainly confirmed by experiments.

Experiments for determining dependence of the refractometer on temperature have shown that the refractive indices obtained from measuring results have to be corrected by the variation of the refractive index of the measuring prism in dependence on temperature if temperatures deviate from 20° C. By means of the method of least squares, from the values reduced corresponding to the glass type an equation for refractive indices has been developed from which tables for refractive indices of sucrose solutions have been cal-culated.