The present studies were focused on foam affinity of various samples including small molecules, macromolecules, and cells as follows: 1. Various pigments were separated with three different types of surfactants: SDS (sodium dodecyl sulfate, anionic), POE-23-LE (polyoxyethylene-23-lauryl ether, neutral) and CPC (cetyl pyridinium chloride, cationic). The results show that basic dyes were collected with SDS foam and acid dyes with CPC foam while none collected with POE-23-LE foam. Addition of NaCl (0.1M) to the surfactant solution shifted the solute peaks toward the liquid outlet in the SDS group and toward the foam outlet in the CPC group whereas addition of methanol (10%) showed no significant effect. 2. The above studies were extended to various non-colored samples including nucleotides and related compounds, peptides and proteins, catecholamines, plant hormones, etc. Among those abscisic acid and indole-3-acetic acid were collected with the CPC foam and bovine insulin with the SDS foam. 3. Various proteins were subjected to foam CCC with 0.2M Na2HPO4 solution containing no surfactant. Bovine serum albumin (BSA) was almost entirely collected with foam while most of other proteins were eluted through both foam and liquid lines with various ratios. 4. With an isotonic saline solution containing BSA as a foam-producing agent, blood cells were subjected to foam separation. Our preliminary studies indicated that platelets were collected with foam while erythrocytes and their membranes were eluted with the liquid stream.
