A further fractionation of agarose

Commercial agarose can be separated into two components by fractional precipitation using alcohols or glycols. The less soluble component has a much higher gel strength and lower endosmosis than the second fraction which can be recovered by salting out or mixing with additional nonsolvent. The ratio of the two fractions over a range of nonsolvent concentrations varies according to the system used. An unanswered question remains regarding the distribution of the fractions - is it bimodal or continuous? Characterization of the fractions and practical applications of the high gel strength fraction will be discussed.