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Chromatographia

, Volume 61, Issue 1–2, pp 17–23 | Cite as

Ethylammonium Acetate as a Mobile Phase Modifier for Reversed Phase Liquid Chromatography

Article

Abstract

We have synthesized the low melting hygroscopic ionic liquid ethylammonium acetate (EAA) and characterized a concentrated solution of EAA as a reversed phase mobile phase replacement for organic solvents like methanol. This solution of EAA acts like an organic solvent with a polarity parameter (P’=6.0) similar to methanol (P’=5.1) but less than water (P’=10.2). A test mixture of salicylate, nitrofurantoin, and acetophenone was separated in this order on C1, C4, and C18 columns using an EAA modified aqueous mobile phase. On a C-18 column, the reduction in retention factor for acetophenone from about 20 to 2 as the % EAA is raised from 20–80% is similar to the same trend found using methanol. However, the retention order using methanol is first nitrofurantoin, then salicylate, and finally acetophenone. Log retention factor (k) versus the volume fraction of either EAA or methanol plots were linear indicating the solvent strength parameter for EAA was about 85% of that for methanol. Despite the relatively high viscosity of EAA, plate count values averaged only about 15% less for EAA as compared to methanol using the same mobile phase composition and could be raised by either working at a temperature above ambient or reducing the flow rate. EAA as a modifier allowed for faster separations of water-soluble vitamins on a reversed phase column designed for totally 100% aqueous mobile phases.

Keywords

Column liquid chromatography Aqueous mobile phase modifier Ethylammonium acetate Water-soluble vitamins 

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References

  1. Davis JM, Fox PA (2003) Chem Commun 11:1209–1212Google Scholar
  2. Marsh KN, Boxall JA, Lichtenthaler R (2004) Fluid Phase Equilibria 219:93–98CrossRefGoogle Scholar
  3. Earle MJ, McCormac PB, Seddon KR (1999) Green Chem 1:23–25CrossRefGoogle Scholar
  4. Adams CJ, Earle MJ, Roberts G, Seddon KR (1998) Chem Commun 19:2097–2098Google Scholar
  5. Stephan MS, Teunissen AJJM, Verzijl GKM, deVries JG (1998) Angew. Chem Intl Ed 37:662–664CrossRefGoogle Scholar
  6. Blanchard LA, Brennecke JF (2001) Ind Eng Chem Res 40:287–292CrossRefGoogle Scholar
  7. Scurto AM, Aki SNVK, Brennecke JF (2002) J Am Chem Soc 124:10,276–10,277CrossRefPubMedGoogle Scholar
  8. Stalcup AM, Cabovska B (2004) J Liq Chromatogr Rel Tech 27:1443–1459CrossRefGoogle Scholar
  9. Vaher M, Koel M, Kaljurand M (2002) J Chromatogr 979:27–32CrossRefGoogle Scholar
  10. Vaher M, Koel M, Kaljurand M (2002) Electrophoresis 23:426–430CrossRefPubMedGoogle Scholar
  11. Vaher M, Koel M, Karjuland M, (2001) Chromatographia 53:S302–S306Google Scholar
  12. Yanes EG, Gratz SR, Baldwin MJ, Robison SE, Stalcup AM (2001) Anal Chem 73:3838–3844Google Scholar
  13. Mwongela SM, Numan A, Gill NL, Agbaria RA, Warner IM (2003) Anal Chem 75:6089–6096Google Scholar
  14. Poole CF, Kersten BR, Ho SSJ, Coddens ME, Furton KG (1986) J Chromatogr 352:407–425CrossRefGoogle Scholar
  15. Shetty PH, Youngberg PJ, Kersten BR, Poole CF (1987) J Chromatogr 411:61–79CrossRefGoogle Scholar
  16. Poole SK, Shetty PH, Poole CF (1989) Anal Chim Acta 24:241–264CrossRefGoogle Scholar
  17. Poole CF (2004) J Chromatogr 1037:49–82CrossRefGoogle Scholar
  18. He L, Zhang W, Zhao L, Liu X, Jiang SJ (2003) J Chromatogr 1007:39–45CrossRefGoogle Scholar
  19. Mihkel K (2000) Proc Estonian Acad Sci Chem 49:145–155Google Scholar
  20. Forsyth SA, Pringle JM, MacFarlane DR (2004) Aust J Chem 57:113–119CrossRefGoogle Scholar
  21. Wilkes JS, Zaworotko MJ (1992) J Chem Soc Chem Commun 13:1965Google Scholar
  22. Miralles E, Prat D, Compano R, Granados M (1997) Analyst 122:553–558CrossRefGoogle Scholar
  23. Gladchikova, Y. N. (1964) Ref Zh Khim Abstract No. 141283Google Scholar
  24. Poole CF (2003) The Essence of Chromatography, Elsevier, Amsterdam, pps. 302, 303, 369Google Scholar

Copyright information

© Friedr. Vieweg&Sohn/GWV Fachverlage GmbH 2004

Authors and Affiliations

  • M. M. Waichigo
    • 1
  • T. L. Riechel
    • 1
  • N. D. Danielson
    • 1
  1. 1.Department of Chemistry and BiochemistryMiami UniversityOxfordUSA

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