IMPROVED METHODS FOR FAT ANALYSIS. 



125 



Formation of chloro-iodo additive compounds with unsaturated acids 

 and their glycerides. 



Solution of excess iodine- with potassium iodide and titration with thio- 

 sulfate, using starch paste as indicator. 



21+2 NaaSaOs = NasS.Oe +2 Nal 



Amount of Material for Different Iodine Numbers. 



[50 cubic centimeters of Wijs solution.] 



200, 

 195, 

 190, 

 185, 

 180, 

 175. 

 170, 

 165, 

 160, 

 155, 

 150, 

 145, 

 140, 

 135, 

 130, 

 125, 

 120, 

 115, 

 110, 

 105, 



Iodine Number. 



Grams of 

 Material. 



Iodine Number. 



100, 

 95, 

 90, 



75, 

 70, 

 65, 

 60, 

 55, 

 50, 

 45. 

 40, 

 35, 

 30. 

 25, 

 20, 

 15. 

 10, 



Grams of 

 Material. 



.64 



.67 



.71 



.75 



.79 



.85 



.91 



.98 



1.06 



1.16 



1.2S 



1.42 



1.59 



1.82 



2.13' 



2. .55' 



3.19' 



4.25' 



6.38' 



12.75 » 



' Take 2 grams. 



- Take 2 grams and use 25 cubic centimeters of Wijs solution. 



Supplementary Notes. — Unsaturated acids and their glycerides assimi- 

 late halogens with the formation of saturated compounds, and this prop- 

 erty serves as a basis for their quantitative determination. Theoretically, 

 chlorine, bromine, iodine, iodobromide or iodochloride may be employed 

 for the purpose. The use of clilorine, however, is impractical, and bromine 

 tends to form both substitution and addition products. Iodobromide 

 (Hanus solution) has no advantage over iodochloride (Wijs solution) 

 except ease of preparation; therefore the latter process, employing the 

 same active agent (iodine monochloride), and agreeing closely with the 



