Planar Chromatography As A Method Of Fractionation Of A Coal Liquefaction Extract For Mossbauer Spectroscopy

In previous work, fractionation into solubility classes and by planar chromatography has aided observation of the distinct characteristics of some less abundant fractions of coal-derived liquids, notably in cases where the signal from the less abundant fraction would otherwise have been swamped by that from the rest of the sample, In this study, fractions of a coal liquefaction extract have been separated by planar chromatography and characterized by Mossbauer spectroscopy, size- exclusion chromatography (SEC), and UV-fluorescence spectroscopy (UV-F), in an attempt to distinguish between the forms and chemical environments of iron found in the coal extract.Size-exclusion chromatograms and UV-F spectra clearly showed structural differences between the separated fractions, The iron complexes present in these fractions gave Mossbauer spectra that were similar to each other, however, and to the spectrum of the whole extract.The work indicates that the Fe2+ and Fe3+ ions are held in similar environments within molecules of different polarities and complexities spanning the range of the separated fractions, No evidence has been found for chemical reaction between the iron centers and the solvents used for the separation, Although Mossbauer determinations are not quantitative, similarities between spectral intensities suggest that the three fractions contain approximately similar amounts of iron.