Rapid analytical methods for colour and ash in raw sugar

A rapid and simple colour measurement method was developed using 0.01M MOPS buffer to maintain pH 7 and filtering 10 g1100 mL sugar solution through a 0.45 pm syringe filter. Results obtained from 100 raw sugar samples by the new rncthod and the current method are similar for Brand 1 and VHP but JA results show an incrcasc ol3.6%. The ICUMSA method of ash measurement by conductivity was compared with the current gravirnetric method on 179 affined and raw sugar samples. An overall incrcasc of 12.5% was observed when measurement was carried out by thc conductimetric method compared with the gravimetric method. Thcrc is a 10% deduction for sulphation applied to the industry's gravimetric ash method and when allowance i s made Tor this the two methods agree well. This result was confirmed in another similar study performed by the New York Sugar Trade Laboratory and Domino Sugar Corporation. The agreement between the methods varied slightly according to districts with the lowest values for conductivity ash being recorded in the north and the highest in the southern district. Kchults for Brand VHP were generally higher than those for other brands and thc reason for this was not readily apparent and will be invchtigatcd furthcr.