DETERMINATION OF THE MOLECULAR-MASS OF POLYGALACTURONIC ACID

A study has been made for the determination of the molecular mass of p olygalacturonic acid in aqueous solution (0.005 mol lithium-oxalate, 0 .05 mol lithium-phosphate, pH = 7.3). Starting out from natural (citru s) pectin, we produced, by heat degradation and alkaline hydrolysis, f inally fractionation with iso-propanol, standard sodium salt of polyga lacturonic acid fractions, the molecular masses of which were determin ed by light scattering measurements. With calibrated sodium polygalact uronate salt fractions, we developed a technology for the determinatio n of viscosimetric molecular masses, in which the Mark-Houwink equatio n is: [eta] = 4.368 10(-7) M1.8737 We conducted gel-chromatographic st udies on a micro-column with calibrated sodium polygalacturonate salt samples. Chromatograms were evaluated with the help of eluent volumes belonging to the peak height. By the above methods, we have measured t he molecular mass of polygalacturonate samples originating from commer cial pectins.