1-methyl-3-octylimidazolium-bromide and 1-butyl-3-methylimidazolium-tetrafluoroborate

The effects of several ionic liquids (ILs) as mobile-phase additives in HPLC with fluorescence and UV-Vis detection for the determination of six heterocyclic aromatic amines were evaluated using two different C(18) stationary phases with moderate silanol activity. The studied ILs were 1-butyl-3-methylimidazolium tetrafluoroborate, 1-hexyl-3-methylimidazolium tetrafluoroborate and 1-methyl-3-octylimidazolium tetrafluoroborate. The optical behaviour of heterocyclic aromatic amines in presence of ILs was studied and the silanol-suppressing potency of ILs was evaluated for the two stationary phases studied. Several chromatographic parameters were evaluated in the presence or absence of ILs, or using triethylamine, the most common mobile-phase additive. The best results were achieved using 1 mM 1-butyl-3-methylimidazolium tetrafluoroborate as mobile-phase additive and NovaPak column. In these conditions and with 18% of ACN in the mobile phase, analytical performance of the chromatographic methods using fluorescence and UV-Vis were evaluated, obtaining good precision in all cases (RSD lower than 6.6%) and low LOD (0.001-0.147 microg/mL with UV-Vis and 0.001-0.006 ng/mL with fluorescence detection).

Topics: Amines; Carbolines; Chromatography, High Pressure Liquid; Heterocyclic Compounds; Imidazoles; Ionic Liquids; Polycyclic Aromatic Hydrocarbons; Silanes; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet

This study investigates the influence of the two different clay minerals kaolinite and smectite as well as of organic matter on the cation sorption and desorption behaviour of three imidazolium based ionic liquids -1-butyl-3-methyl-imidazolium tetrafluoroborate (IM14 BF(4)), 1-methyl-3-octyl-imidazolium tetrafluoroborate (IM18 BF(4)) and 1-butyl-3-methyl-imidazolium bis[(trifluoromethyl)sulfonyl]imide (IM14 (CF(3)SO(2))(2)N) - in soil. The German standard soil Lufa 2.2 - a natural soil classified as a loamy sand - was the basis substrate for the different soil compositions and also served as a reference soil. The addition of organic matter and clays increases the sorption of the substances and in particular smectite had striking effects on the sorption capacity for all three ionic liquids indicating that ionic interactions play an important role for sorption and desorption processes of ionic liquids in soil. One exception was for kaolinite-containing soils and the IM14 cation: with (CF(3)SO(2))(2)N(-) as an anion the sorption was identical at either 10 wt% or 15 wt% clay content, and with BF(4)(-) sorption was even lower at 15 wt% kaolinite than at 10 wt%. Desorption was weak for IM18 BF(4), presumably owing to the longer alkyl side chain. With regard to the influence of kaolinite on desorption, the same pattern was observed as it was found for the sorption of IM14 BF(4) and IM14 (CF(3)SO(2))(2)N.

Topics: Adsorption; Aluminum Silicates; Clay; Imidazoles; Ionic Liquids; Kaolin; Kinetics; Silicates; Soil