Abstract: The colour of white sugar in filtered aqueous solution is determined photometrically as multiple of the absorbency index and expressed in ICUMSA Units (IU).
This method without adjustment of the pH of the solution is limited to colour values up to 50 IU.
The method can be applied to all crystalline or powdered white sugars and very pure syrups (General Subjects 2 and 3), provided that a filtered test solution can be prepared by the procedure specified in the method.
The method is not suitable for those sugars which contain colouring matter, turbidity or additives to an extent that filtration is not practical.
If a choice is available to the user for the determination of colour of white sugar, then ICUMSA recommends that Method GS9-8 is used preferentially.
However, it should be noted that Method GS2-10 gives equivalent results to Method GS9-8 up to a maximum value of 50 IU.
For sugars with ICUMSA Colour values up to 50 IU, the absolute difference between two results, obtained under repeatability conditions, should not be greater than 3 IU.
For sugars with ICUMSA Colour values up to 50 IU, the absolute difference between two results, obtained under reproducibility conditions, should not be greater than 7 IU.
Precision data are determined and valid only for crystalline white sugar in the colour range of 5.8 IU to 34.7 IU.
Online Access to ICUMSA Method GS2/3-10 (2011)
Access to the online Version of ICUMSA Method GS2/3-10 (2011) can be obtained from the Sugar Industry Website, operated by Bartens. The online access for two years costs EUR35 (+ 19 % VAT for German and EU citizens without EU VAT No.).