ABSOLUTE CALIBRATION OF SIZE-EXCLUSION CHROMATOGRAPHY FOR COAL DERIVATIVES THROUGH MALDI-MS

This paper reports the fractionation and subsequent examination of two , very different coal derived materials, a coal tar pitch and a commer cial liquefaction extract. These were separated on the basis of their retention in a typical preparative size exclusion chromatography appar atus using THF as the eluent. Matrix assisted laser desorption mass sp ectrometry, using the small molecules of the sample as matrix, has bee n used to examine the various fractions from preparative s.e.c. and th e peak mass intensities have been used to define an absolute calibrati on of the s.e.c. separation. Limitations of the methods are discussed. The u.v.-fluorescence spectra of the fractions were recorded and tren ds in the spectra are described. The fractions were also analyzed by s ize exclusion chromatography employing N-methyl-2-pyrrolidinone as the chromatographic eluent. The main advantages of this system over tradi tional solvents is the avoidance of surface adsorption effects observe d with THF and the more complete solution of coal-derived material. (C ) 1998 Elsevier Science Ltd. Ail rights reserved.