ISI 06-1e Determination of Dry Matter in Syrup by Refractive Index
ISI 06-1e Determination of Dry Matter in Syrup by Refractive Index 1. Scope The method is applicable to glucose, maltose and fructose syrup JK 03. Feb. 1967 Rev. LT 24 Nov. 1997 2. Principle The refractive index of sample is transformed to dry matter by a polynominal function or table. 3. Apparatus 3.1 Refractometer, thermostated 4. Procedure Adjust temperature of refractometer (3.1) to 45 o C. Degree Celcius = t Adjust sample temperature to that chosen for the refractometer. Place a few drops of sample on fixed prism and close instrument Work fast Read the refractive index (n D45 ) to nearest 0.0002 unit. Clean prisms immediately after. 5. Calculation Correct index to index at 45 o C (n D45 ) if not measured at 45 o C temperature and calculate dry matter (DM) in percent of sample (average results of two samples with no decimal): n D45 = 0.000065 * n D * (45-t) * n D 3 DM % = a * n D45 2 + b * n D45 + c Within the indicated range of dry matter the results is in