Abstract: A method for adsorption of a substance from a liquid sample on a fluidized bead or stirred suspension, in which the beads used comprise a base matrix and exhibit a structure having affinity to the substance, characterized in that the structure is covalently bound to the base matrix via an extender. Populations of beads in which the beads contain a filler incorporated in a base matrix and an extender are also described.

Abstract: A medium for isoelectric focusing is produced which consists of or contains agarose into which positively charged substituents have been introduced to neutralize negatively charged groups inherently present in the agarose, said substituents containing as the only charged group a quaternary amino group with a positive charge independent of pH at least in the range 2-12. The medium may consist of a mixture of two or more agarose preparations with different degrees of substitution with regard to the introduced substituents. Unmodified agarose may also constitute one of the components of the medium.