Ionic liquids as solvents in headspace gas chromatography

Abstract

A method of using an ionic liquid as solvent in headspace gas chromatography.

1 . A method of performing headspace gas chromatography using an ionic liquid having a vapor pressure of essentially none, less than about 1 mm/Hg at 25° C., and less than about 0.1 mm/Hg at 25° C., the ionic liquid further having a thermal stability of from 150° C. to 400° C. 
     
     
         2 . The method of  claim 1  wherein the ionic liquid has a thermal stability of from 200° C. to 300° C. 
     
     
         3 . The method of  claim 1  wherein the ionic liquid has essentially no vapor pressure. 
     
     
         4 . The method of  claim 1  wherein the ionic liquid has a vapor pressure of less than about 1 mm/Hg at 25° C. 
     
     
         5 . The method of  claim 1  wherein the ionic liquid has a vapor pressure of less than about 0.1 mm/Hg at 25° C. 
     
     
         6 . The method of  claim 1  wherein the ionic liquid has a thermal stability of from 150° C. to 400° C. 
     
     
         7 . The method of  claim 1  wherein the ionic liquid has a thermal stability of from 200° C. to 300° C. 
     
     
         8 . The method of  claim 1  wherein the ionic liquid has a vapor pressure of less than about 1 mm/Hg at 25° C. and a thermal stability of from 150° C. to 400° C. 
     
     
         9 . The method of  claim 1  wherein the ionic liquid has a vapor pressure of less than about 1 mm/Hg at 25° C. and a thermal stability of from 200° C. to 300° C. 
     
     
         10 . The method of  claim 1  wherein the ionic liquid comprises an anion selected from the group consisting of Cl − , Br − , NO 2   − , NO 3   − , AlCl 4   − , BF 4   − , PF 6   − , CF 3 COO − , CF 3 SO 3   − , (CF 3 SO 2 ) 2 N − , OAc − , CuCl 3   − , GaBr 4   − , GaCl 4   − , and SbF 6   − . 
     
     
         11 . The method of  claim 1  wherein the ionic liquid comprises a cation selected from the group consisting of pyridinium, ammonium, imidazolium, phosphonium, and sulphonium. 
     
     
         12 . The method of  claim 1  wherein the ionic liquid is selected from the group consisting of 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium methane sulfonate, 1-hexyl-3-methylimidazolium hexafluorophosphate, 1-octyl-3-methylimidazolium hexafluorophosphate, 1-decyl-3-methylimidazolium hexafluorophosphate, 1-dodecyl-3-methylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium bis((trifluoromethyl)sulphonyl)amide, 1-ethyl-3-methylimidazolium trifluoromethansulfonate, 1-ethyl-3-methylimidazolium bis((trifluoromethyl)sulphonyl)imidate (I), 1-ethyl-3-methylimidazolium bis((trifluoromethyl)sulphonyl)imidate (II), 1-hexyl-3-methylimidazolium bis((trifluoromethyl)sulphonyl)amide, 1-hexylpyridinium tetrafluoroborate, 1-octylpyridinium tetrafluoroborate, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-methyl-3-ethyl imidazolium chloride, 1-ethyl-3-butyl imidazolium chloride, 1-methyl-3-butyl imidazolium chloride, 1-methyl-3-butyl imidazolium bromide, 1-methyl-3-propyl imidazolium chloride, 1-methyl-3-hexyl imidazolium chloride, 1-methyl-3-octyl imidazolium chloride, 1-methyl-3-decyl imidazolium chloride, 1-methyl-3-dodecyl imidazolium chloride, 1-methyl-3-hexadecyl imidazolium chloride, 1-methyl-3-octadecyl imidazolium chloride, 1-methyl-3-octadecyl imidazolium chloride, ethyl pyridinium bromide, ethyl pyridinium chloride, ethylene pyridinium dibromide, ethylene pyridinium dichloride, butyl pyridinium chloride, benzyl pyridinium bromide, and mixtures thereof, and volatilizing the volatile components of the sample by headspace gas chromatography. 
     
     
         13 . The method according to  claim 12  wherein the ionic liquid is selected from the group consisting of 1-butyl-3-methylimidazolium methane sulfonate, 1-ethyl-3-methylimidazolium trifluoromethansulfonate, 1-ethyl-3-methylimidazolium bis((trifluoromethyl)sulphonyl)imidate (I), and 1-ethyl-3-methylimidazolium bis((trifluoromethyl)sulphonyl)imidate (II).