218 Messrs Jones and Carpenter, Estimation of Hydroxylamine. 



The Estimation of Hydroxylamine (Preliminary note). By 

 H. O. Jones, M.A., Clare College, and F. W. Carpenter, Clare 

 College. 



[Heceived 16 June 1903.] 



The authors found that the methods hitherto described for the 

 estimation of hydroxylamine in solution were very unreliable, 

 especially in presence of impurities such as metallic salts and 

 carbon dioxide. 



An attempt was then made to see if a method could be 

 elaborated which was free from these objections, and it was found 

 that hydroxylamine could be estimated with ease and accuracy by 

 the method described by Wood and Berry (Proc. Gamb. Phil. Soc. 

 XII. ii. 97) for the estimation of reducing sugars. 



Ten to twenty cubic centimetres of a solution of hydroxylamine 

 and one of its salts (containing not more than 0'5 °/ NH 2 OH) are 

 run from a pipette into 30 c.c. of a boiling solution of copper in 

 potassium bicarbonate (Soldani) or Fehling's solution, with stirring, 

 the whole raised to the boiling-point, and the cuprous oxide 

 immediately filtered off, washed, dissolved in some ferric sulphate 

 solution in an atmosphere of carbon dioxide and the ferrous salt 

 produced titrated with potassium permanganate. 



In dilute solution ("5 °/ ) the reaction between hydroxylamine 

 and copper oxide may be expressed by the equation 



2NH 2 OH + 4CuO = N 2 + 2Cu 2 + 3H 2 0, 



so that in the titration with permanganate 4 gram molecules of 

 permanganate correspond to 10 gram molecules of hydroxylamine, 

 or 632 grams to 330 grams. 



The effect of other substances, which themselves have no action 

 on the copper solution, is negligible, e.g. that of salts, alcohol and 

 ketoximes was tried. 



