LESSON IV 



TESTING FOR ALBUMOSES 



151 



Albumoses 



Tests for albumoses. 



Solutions of albumoses are supplied. 



(a) Proto-albumose (concentrated 

 solution). 



(1) Boil : no coagulation. 



(2) Biuret test : pink colour. 



(3) Ammonium sulphate : pre- 

 cipitate. 



(4) Alcohol : precipitate. 



(5) Equal volume of concentrated 

 solution of sodium chloride in acetic 

 acid : precipitate. 



Boil : precipitate disappears. 



Allow to cool : precipitate re- 

 appears. 



(6) Concentrated aqueous solu- 

 tion of sodium chloride : precipi- 

 tate. 



(7) Add nitric acid, drop by drop, 

 keeping the solution cool : pre- 

 cipitate, soluble in excess of nitric 

 acid. 



Warm gently : precipitate dis- 

 appears. 



Cool again : precipitate re- 

 appears. 



(8) Excess of picric acid : pre- 

 cipitate. 



(9) Neutral copper sulphate : 

 turbidity or precipitate. 



(10) Boil with Millon's reagent : 

 red precipitate or colour. 



(b) Deutero - albumose (concen- 

 trated solution). 



(1) Boil : no coagulation. 



(2) Biuret test: pink colour. 



(3) Ammonium sulphate : pre- 

 cipitate. 



(4) Alcohol : precipitate. 



(5) Equal volume of concentrated 

 solution of sodium chloride in acetic 

 acid: precipitate. 



Boil : precipitate disappears. 



Allow to cool : precipitate re- 

 appears. 



(6) Concentrated aqueous solu- 

 tion of sodium chloride : no pre- 

 cipitate. 



Now add also acetic acid satu- 

 rated with sodium chloride : 

 precipitate. 



(7) Add nitric acid, drop by drop, 

 keeping the solution cool : no pre- 

 cipitate. 



Add a few crystals of sodium 

 chloride first and then nitric 

 acid, drop by drop, keeping 

 the solution cool: precipitate, 

 which disappears on warming 

 and reappears on cooling. 



(8) Excess of picric acid : pre- 

 cipitate. 



(9) Neutral copper sulphate : 

 precipitate. 



(10) Boil with Millon's reagent : 

 red precipitate or colour. 



