Separation And Analysis Of Thermally Dissolved Products From Zhaotong Lignite And Wucaiwan Long Flame Coal Using Chromatographic Methods

Zhaotong lignite(ZL)and Wucaiwan long flame coal(WLFC)were sequentially dissoluted at 300 oC to afford soluble portions(SPs).SPs were separated and analyzed by three chromatographic methods,gas chromatography-mass spectrometry(GC-MS),comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry(GC×GC-TOF MS),and high-performance liquid chromatography time-of-flight mass spectrometry(HPLC-TOF MS).In the meantime,SPs were separated by silica gel column chromatography and the subfractions were analyzed using GC-MS.The GC-MS analytical results of SPs indicate that the ralative abundances of alkanes,arenes and phenols were higher in cyclohexane-thermal soluble portions.In acetone-thermal soluble portions,a higher ralative abundance of phorone was detected.For methonal-thermal soluble portions,higher ralative abundances of alcohols and phenols were detected.After further separation of each SPs by column chromatography,all kinds of fractions were enriched and mainly include: alkanes,aromatics in cyclohexane-thermal soluble portions and phorone in acetone-thermal soluble portions.GC×GC is one of the most powerful separational tools,because it has two capillary columus with different polarities to separate complex substances.When GC×GC is coupled with TOF MS,the deconvolution of some overlapping peaks and identification of compounds with close m/z become possible.Anlytical results of the acetone SPs of WLFC via GC×GC-TOF MS were discussed in-depth.GC×GC-TOF MS is more suitable for the characterization of polycyclic aromatic hydrocarbons,oxygen-containing,nitrogen-containing and sulfur compounds with relatively low abundance,due to its high peak capacity,high sensitivity and high resoloving power.Heteroatomic compounds in SPs were well detected by HPLC-ESI-TOF MS because of the ionization selectivity of ESI source.Some isomers in the SPs were separated and identified by HPLC-TOF MS,and the corresponding structural informations were proposed.Oxygen-containing compounds are thought to be mainly hydroxyl and carbonyl groups in SPs.Nitrogen-containing compounds in SPs were identified in the form of pyridine ring and amino.Sulfur-containing species mainly exist in sulfane and thiophene.