SIZE-EXCLUSION CHROMATOGRAPHY OF LIGNIN AS ION-PAIR COMPLEX

A high-performance ion-pair size-exclusion chromatography method was d eveloped for analysis of underivatised lignin samples using styrene-di vinylbenzene gel columns with tetrahydrofuran as solvent. An extractio n method using the quaternary amine methyltrioctylammonium chloride al lowed quantitative extraction of kraft lignin, lignosulfonic acids and Organosolv lignins from alkaline solution to various organic solvents . Quaternary-amine complexes of lignins formed were analysed by an ion -pair type size-exclusion chromatography in 20 mM quaternary amine in tetrahydrofuran. Intermolecular association and adsorption on the matr ix was overcome without sample derivatisation. It was possible to anal yse various types of lignins and dehydropolymer-lignin model compounds using the same universal analytical system.