CANE SUGAR. 



than with solutions clarified with neutral acetate of lead, and the writer is of 

 the opinion that results closest to the truth are obtained with the use of this 

 material. In case clarification with a lead salt is used, the excess of lead 

 must he removed ; this may be done by the addition of a soluble sulphate, 

 carbonate or oxalate. 



The International Commission for Uniform Methods of Sugar Analysis, 

 sitting in London in 1909, failed to agree on this point ; basic lead acetate 

 was forbidden, and neutral lead acetate was objected to by the English chemists 

 only, so that no agreement was reached. 



With no treatment at all the gravimetric process is impracticable with low 

 grade products, owing to filtration being impossible ; clarification with alumina 

 cream will almost invariably overcome this difficulty. 



Determination of Cane Sugar as Glucose. On treatment 

 with acids cane sugar is quantitatively converted into equal parts of dextrose 

 and levulose, the mixture of the two being known as invert sugar; from 

 100 parts of cane sugar there are obtained 105*32 parts of invert sugar. 



In most text books the scheme given is to determine the invert sugar in 

 the sample before inversion. Let the invert sugar be in a sugar, say, 2*0 per 

 cent. The sugar is then inverted and is now found to contain, say, 103*6 per 

 cent, sugar, calculated as invert sugar ; deducting the invert sugar there 

 remains 101-6 per cent, cane sugar as invert sugar, and this converted to cane 

 sugar by dividing by 1-0532, or by multiplying by -95, gives the invert sugar 

 as 96*52 per cent. 



If this scheme is to be used as an accurate one it is essential that gravi- 

 metric processes be used to estimate the glucose, that the effect of the presence 

 of cane sugar in determining the glucose originally present be allowed for, and 

 that the correct factors connecting weight of copper be obtained. An example 

 of the method of calculation is appended. 



Ten grms. raw sugar were dissolved in 100 c.c., and 25 c.c. (= *4 grm. 

 sugar) treated according to Allihn's process ; there were obtained 84-6 mgrms. 

 copper = 43-2 mgrms. dextrose, equivalent to 45*1 mgrms. as invert sugar; 

 hence the material contains approximately 1*13 per cent, reducing sugars as 

 invert sugar. 10 c.c. of the above solution were inverted, neutralized, and 

 made up to 200 c.c. 25 c.c. (= -125 grms. sugar) treated according to 

 Allihn's process gave 237-4 mgrms. copper rr 122-5 mgrms. dextrose = 127*7 

 mgrms. invert sugar, or 102*32 per cent, total sugar as invert sugar. Deduct- 

 ing the invert sugar already found as present before inversion, there is due to 

 the cane sugar 101*09 per cent, as invert sugar, which, converted to cane 

 sugar, gives 96*04 per cent, as the approximate amount of cane sugar. 

 Applying Browne's correction, t.*., dividing the grms. sucrose in the 25 c.c. of 

 solution to be analysed by Allihn's method by the mgrms. of dextrose found 

 + 40, the calculation appears : Approximate amount of cane sugar in 25 c.c. 



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