Simplified apparatus for technical sugar colorimetry

Abstract

The apparatus consists of a Duboscq colorimeter and an incandescent li ght source with suitable spectral filters and glass photometric standa rds for the measurement of absorbancy in sugar solutions. The a bsorbancy of all except very pale solutions, may be determined at 560 m}.! by using a special yellow-green filter. Solutions of high-grade sugar products having little color a re treated as a special case, and using a blue filter, measurements are made at 460 m}.!. The results obtainable are satisfactory for technical purposes.

Spectrophotometric Studies on Refined Sugars in Solution

“…The calibration curve for the proposed method is shown in Figure 4, in which per cent absorptancy (100 -% transmittancy) is plotted against log concentration. The maximum attainable photometric accuracy, evaluated from the slope of the curve, is 2.9% relative error per 1% absolute photometric error, conforming closely to derivations from Beer's law (1); for an absolute photometric error of 0.2%, the relative analysis error is therefore 0.6%. Maximum accuracy occurs at about 5 p.p.m.…”

“…a, 560 mg = 0.169128 -0.00084 brightness -0.00021 purity -0.00015 dominant wave length (1) The correlation coefficient between the absorbancy index at 560 mg and the monochromatic analysis is 0.9927.…”