ELUTION PATTERNS OF AQUATIC HUMUS IN SIZE EXCLUSION CHROMATOGRAPHY BASED ON DIFFERENT ELUANTS.

Elution patterns of aquatic humus were analysed with a Sephadex G-100 column and employing five different series of eluants, the other conditions being constant. The eluants used were: (1) pH regulated distilled water, (2) NaCl solutions with different ionic strengths and constant pH, (3) phosphate buffers with increasing pH and conductivity, (4) Tris buffer eluants with increasing pH and decreasing conductivity, and (5) urea solutions of different concentrations. At neutral pH and low ionic strength, dissolved humic matter consists of five component fractions, which can be detected with combined UV- and fluorescence monitoring. At higher ionic strength the number of peaks is reduced from five to two, which are the excluded peak and the retarded peak near the inclusion limit of the column.