A general method for quantitative separation of prostaglandins by paper chromatography

Abstract

Although prostaglandin (PG) mixtures have previously been resolved by chromatography on silica-impregnated paper, drawbacks inherent in each technique have kept them from becoming generally accepted for routine analytical separations. Singh and co-workers (1,2) obtained excellent separation of prostaglandin mixtures on silica-impregnated glass fiber paper. However, this paper was not commercially available and its preparation is tedious. On the other hand, Stamford and Unger (3) separated PGE and PGF on commercially available paper using benzene/chloroform/acetone/methanol/acetic acid as developing solvent. Nevertheless, this solvent does not resolve less polar prostaglandins and fatty acids. More generally acceptable solvent systems cannot be used quantitatively with Stamford and Unger's technique due to irreversible binding of prostaglandins at the origin. Tobias and Paulsrud (11) have separated prostaglandins on commercial silicic acid-impregnated glass fiber sheets, but these are extremely brittle and difficult to accommodate to standard paper radiochromatogram scanners. This communication describes the quantitative chromatographic separation of PGF 1α, PGE 2, PGA 1, and arachidonic acid on commercially available Whatman SG-81 silica-impregnated paper using a wide variety of developing solvents. Irreversible binding of prostaglandins at the origin, previously a serious drawback, has been eliminated by applying the sample onto premoistened paper. This method is quantitative, sensitive, reproducible, and applicable to a variety of solvent systems. In addition, it is simple and inexpensive. Although loading capacity is somewhat limited, this is no problem with prostaglandins since they can be readily concentrated in organic solvents.