- 127 - 



As a rule the electroosmotic flow is greater when electrode -vessels 

 are employed than when the electrodes are applied directly to the 



Q 



migration medium°i> 



Sub s tanoes Separated by Eleotrochromatography 



Many different kinds of substances have now been examined by 



electrochromatographyo All kinds of inorganic cations and anions 



1 c A 7 

 have been studied under a great variety of conditions^* -'» *'» 



For the separation of the rare earth cations, the method is 

 very selective when the ions are sorbed on the paper stabilization 

 medium or when they form complexes with tartrate ions-^9o (See Fig- 

 ure V, 5<,) For the separation of alkaline earth cations, the electri- 

 cal migration is more selective in the presence of anmonium citrate 

 (see Figure V,6) than in citric acid solutiono Although lithium, 

 sodium, and potassium ions are readily separable, potassium, cesium, 

 and rubidium ions are inseparable9 as indicated in Figure V,6o 



Various inorganic anions such as the oxy acids of phosphorus 

 separate readily in a particular sequence' o (See Figure V,7o) The 

 mobility of phosphate is a function of pH^^. The oxy acids of sulfur 

 also separate easilyo 



In all these separations there is no systematic relationship 

 between the oxidation state of an element and the electrochromatog= 

 raphic sequence„ There is also little relationship between the sepa- 

 rability of ions by electromigration and by the usual chemical methods o 



Many ionized organic substances have been separated by electrical 

 migration. These include various acids and bases, especially the amino 

 acidso Many nonionized organic substances such as aldehydes, ketones. 



