Raffinose paper chromatography

De Whalley and his coworkers have made extensive studies on the application of paper chromatography to raffinose. To separate raffinose from large proportions of sucrose, a 1-butanol-benzene-pyridine-water solvent was used.140 81 To avoid pyridine, a 1-propanol-ethyl acetate-water mixture was recommended.141 As a color reagent, a-naph-thol-phosphoric acid was used. In this manner, less than 1 % of raffinose in cane sugar could be separated and determined. Partial hydrolysis of the raffinose, using invertase directly on the filter paper, proved useful in some instances.93 142 Melibiose was then detected with 3,5-dinitrosali-cylate142 or with diethyl-p-phenylenediamine sulfite.93... 

A sample of green bean seeds (Black Valentine) was extracted with cold ether to remove fats, and then extracted with hot methanol and analyzed by paper chromatography. Raffinose was found besides other sugars. Analysis of an aliquot by an ion exchange procedure showed the raffinose content to be 0.40 mg., present in the fraction between approximately 80 and 180 ml. of the eluate. Separation and recovery of 1 mg. each of sucrose, raffinose, stachyose, and fructose in a mixture of pure sugars were checked by the same procedure and found to show a recovery of 1.02 mg. for raffinose. 

This problem is acute in sugar analysis when dealing with samples of raw sugars with raffinose contents of mostly below 0.5%. The need was filled by the development of a method based on the findings of Partridge (68) that, under suitably chosen conditions, raffinose can be separated by paper chromatography from the other sugars and thus can be directly determined by any appropriate method of analysis. 

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