THE ASSAY OF SUGAR HOUSE PRODUCTS. 



efficiency of any new methods of clarification. Perhaps the most con- 

 venient process is Gunning's modification of the original Kjeldahl moist 

 combustion process. In this process the material under analysis is heated with 

 a mixture of sulphuric acid and potassium sulphate, until the solution has 

 become colourless or of a pale straw colour. As applied to cane juice the 

 process may be thus conducted : 20 c.c. of juice are evaporated to small bulk 

 and washed into a 300 c.c. hard glass flask with 20 c.c. of concentrated 

 sulphuric acid ; add, in small quantities at a time, lOgrms. powdered potassium 

 sulphate ; heat very gently over a small flame till frothing stops, and then 

 raise the temperature and allow to boil till the contents of the flask are colour- 

 less ; transfer to a hard glass litre flask, add caustic soda to distinct alkalinity 

 and distil until all the ammonia is given off, collecting the distillate in 50 c.c. 

 of decinormal acid ; determine the excess of acid remaining by titration with 

 decinormal alkali ; bumping nearly always occurs near the end of the 

 distillation, and to prevent this, the latter operation may be carried out by a 

 current of steam, the flask itself being gently heated by a small flame. The 

 caustic soda should be introduced through a stoppered thistle funnel and the 

 distillation flask provided with a safety bulb to prevent any of the contents of 

 the flask being carried over mechanically. The sulphuric acid used should be 

 tested by means of a blank experiment for nitrogen and the quantity found 

 deducted from subsequent determinations. 



Determination Of Amides 13 . The material is boiled for one hour 

 with a 5 per cent, solution of sulphuric or hydrochloric acid, at the end of 

 which time the amide nitrogen is converted into ammonium salts ; after exact 

 neutralization with sodium carbonate the material is distilled over magnesia 

 free of carbonates, and the distillate is collected in standard acid and the 

 ammonia evolved determined in the usual way. Half the nitrogen of the 

 amide bodies is thus obtained as ammonia ; it is customary to calculate the 

 ammonia thus obtained to asparagin C 4 H 8 N 2 3 ; if ammonia salts are present 

 these are determined separately. 



Determination of Albumenoid Nitrogen 13 . Place -7 grm. 

 of the substance in a beaker, add 100 c.c. of water, and heat to boiling; add 

 a quantity of Stutzer's reagent containing about '5 grm. copper hydroxide, 

 filter when cold, wash with cold water, and determine the nitrogen in the 

 precipitate. 



Stutzer's reagent is thus prepared: dissolve 100 grms, copper sulphate 

 in 5 litres of water, add 2'5 c.c. glycerol, and then a dilute solution of sodium 

 hydroxide until the solution is just alkaline ; filter, rub the precipitate up 

 with water containing 5 c.c. of glycerol per litre, and wash by decantation on 

 filtration until the washings are no longer alkaline. Rub the precipitate up 

 again in a mortar with water containing 10 percent, of glycerol, thus preparing 



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