ON THE DETECTION AND DETERMINATION OF 

 COCONUT OIL.^ 



By H. D. GiBBS and F. Agcaoeli. 

 (From the Laboratory for the Investigation of Foods and Drugs, Bureau of 



Science, Manila, P. I.) 



Hodgson - describes what purports to be an accurate method for the 

 detection and estimation of coconut oil when used as an adulterant of 

 butter. He states that he has found "the quantit_y of oxygen required 

 to oxidize a given quantity of the saponified fat, is, in the case of butter 

 fat, invariable." ' In the case of coconut oil he finds the quantity of 

 oxygen required to vary considerably in the twenty samples * examined, 

 but the largest amount required by any of the samples is much less than 

 .that used by an equal amount of butter fat.'' Hodgson maintains that 

 the composition of mixtures of coconut oil and butter fat has been 

 accurately determined " from this constant. 



The method employed consists in the oxidation of 20 cubic centimeters of a 



N 

 0.1 per cent aqueous solution of the saponified fat with — potassium perman- 

 ganate solution. The oxidation is carried on at the temperature of 100° in 

 tlie presence of a large excess of sulphuric acid and potassium permanganate. 

 The proportions are 20 cubic centimeters of a 0.1 per cent solution of the products 



N 

 of saponification, 50 cubic centimeters of — potassium permanganate and 50 



cubic centimeters of a 50 per cent solution of sulphuric acid. This mixture is 



heated for thirty minutes at a temperature of 100° and the excess of potassium 



N 

 permanganate titrated with -jr oxalic acid or ferrous ammonium sulphate. 



Results of remarkable uniformity were obtained with various mixtures of butter 

 and coconut oil. 



' Since the completion of this paper a nimiber of investigators have found 

 Hodgson's method to be valueless. For the reason that no one has pointed out 

 the real cause for its failure we are perhaps justified in publishing our results, 

 even though we are again proving the fallacy of the method. We have been for 

 some time experimenting upon coconut oil and our investigations in other direc- 

 tions than those chronicled here are being continued. 



'Ghem. News (1907), 96, 273, 288, and 297. 



= Ibid, 273. 



■" Obtained in Birmingham, England. 



= Ibid., 288. 



'Ibid, 297. 



371 



