Abstract
The results obtained through investigation of various methods for the determination of alginic acid in brown algae are as follows:
1) JENSEN's method gives higher values in alginic acid content in some species of brown algae.
2) Titrimetric method gives lower values in alginic acid content in some species of brown algae. This may due to imperfect extraction of alginic acid in algae.
3. JENSEN's method is modified, and this modified method gives reliable values. The procedure is as follows; organic acids and carbonates in brown algae are extracted at first by alkali ethanol, and then by hydrochloric acid, and alginic acid in the extraction residue is determined by decarboxylation method.
4) In order to shorten the time for the determination of alginic acid in brown algae, decomposition method by caustic alkali is adopted. The results obtained by this method agree with those of the modified JENSEN's method, and the time for the determination of this method is reduced to about one-third of that of the modified JENSEN's method.
