POST-COLUMN COMPLEXATION TECHNIQUE FOR THE SPECTROPHOTOMETRIC DETECTION OF POLY(OXY-1,2-ETHANEDIYL) OLIGOMERS IN STERIC EXCLUSION CHROMATOGRAPHY

A solid-phase complexation column (SPCC), which consists of ammonium cabaltothiocyanate (ACTC) adsorbed on a solid support, has been developed as part of a selective detection technique for molecules bearing one or more poly(oxy1,2-ethanediyl) oligomers (POEs). Due to the ion-dipole attraction between the ammonium ion and the negative dipoles of the polyether oxygen atoms, a quantity of ACTC is solubilized in the mobile phase as the POE-ACTC complex. The complexed ACTC is readily quantitated at 320 or 620 nm because of the strongly absorbing cobaltothiocyanate anion. The detection technique is approximately 100 times more sensitive than the differential refractive index detector for this class of compounds. This detector is used with steric exclusion chromatography on Sephadex LH-20 and μStyragel columns. © 1979.