, Volume 53, Issue 3–4, pp 190–196 | Cite as

Sensitivity enhancement in capillary electrochromatography by on-column preconcentration

  • M. J. Hilhorst
  • G. W. Somsen
  • G. J. de Jong
Originals Electrophoresis


The potential of on-column preconcentration in capillary electrochromatography (CEC) to improve the detection limit was investigated. Two test mixtures containing a pharmaceutically relevant steroid (Desogestrel or Tibolon) together with several structurally related compounds were used for evaluation. For both test mixtures, the mobile phase composition was optimised resulting in a baseline separation of all components and plate numbers of up to 1.2·105 plates m−1 within 15 min. An equation was derived which describes the obtainable gain in injection time as function of the analyte retention factor in the mobile phase and in the injection solvent. The proposed model accounts for the focussing of the analytes due to both the retention during injection and the step-gradient during elution. For the experimental study, the least hydrophobic component of the Desogestrel mixture was used. When the mobile phase was used as injection solvent, a considerable decrease in plate number was observed when the injection time exceeded 5 s. By dissolving the analyte in a less-eluting solvent, injection times could be increased up to 60 s without causing significant extra band broadening. Two mixtures containing a relatively high amount of Desogestrel or Tibolon, and the related components at the 0.1% level were analysed to study the potential of the system for impurity profiling. With the mobile phase as injection solvent, the low level components could hardly be detected. By applying large volume injection from a less-eluting injection solvent, a gain in sensitivity of a factor of 7–9 was achieved.

Key Words

Capillary electrochromatography On-column preconcentration Sensitivity enhancement Desogestrel Tibolon 


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  1. [1]
    Pretorius, V.; Hopkins, B.J.; Schieke, J.D.J. Chromatogr. 1974,99, 23–30.CrossRefGoogle Scholar
  2. [2]
    Knox, J.H.; Grant, I.H.Chromatographia 1987,24, 135–143.Google Scholar
  3. [3]
    Knox, J.H.; Grant, I.H.Chromatographia 1991,32, 317–328.CrossRefGoogle Scholar
  4. [4]
    Dittmann, M.M.; Rozing, G.P.J. Chromatogr. A 1996,744, 63–69.CrossRefGoogle Scholar
  5. [5]
    Hilhorst, M.J.; Somsen, G.W.; de Jong, G.J.J. Chromatogr. A 2000,872, 315–321.CrossRefGoogle Scholar
  6. [6]
    Gillott, N.C.; Euerby, M.R.; Johnson, C.M.; Barrett, D.A.; Shaw, P.N.Anal. Commun. 1998,35, 217–220.CrossRefGoogle Scholar
  7. [7]
    Lurie, I.S.; Conver T.S.; Ford, V.L.Anal. Chem. 1998,70, 4563–4569.CrossRefGoogle Scholar
  8. [8]
    Terabe, S.; Ichikawa, K.; Tsuchiya, A.; Ando, T.Anal. Chem. 1984,56, 111–113.CrossRefGoogle Scholar
  9. [9]
    Yang, L.; Lee, C.S.J. Chromatogr. A 1997,780, 207–213.CrossRefGoogle Scholar
  10. [10]
    Smith, N.W.; Evans, M.B.Chromatographia 1994,38, 649–657.CrossRefGoogle Scholar
  11. [11]
    Euerby, M.R.; Christopher, C.M.; Johnson, M.; Bartle, K.D.; Myers, P.; Roulin S.C.P.Anal. Commun. 1996,33, 403–405.CrossRefGoogle Scholar
  12. [12]
    Euerby, M.R.; Gilligan, D.; Christopher, C.M.; Johnson, M.; Roulin, S.C.P.; Myers, P.; Bartle, K.D.J. Microcol. Sep. 1997,9, 373–387.CrossRefGoogle Scholar
  13. [13]
    Lane, S.J.; Boughtflower, R.; Paterson, C.; Underwood, T. Rapid Commun.Mass Spectrom. 1995,9, 1283–1287.Google Scholar
  14. [14]
    Angus, P.D.A.; Victorino, E.; Payne, K.M.; Demarest, C.W.; Catalano, T.; Strobaugh, J.F.Electrophoresis 1998,19, 2073–2082.CrossRefGoogle Scholar
  15. [15]
    Wang, J.; Schaufelberger, D.E.; Guzman, N.A.J. Chrom. Sci. 1998,36, 155–160.Google Scholar
  16. [16]
    Reilly, J.; Saced, M.J. Chromatrogr. A 1998,829, 175–186.CrossRefGoogle Scholar
  17. [17]
    Albin, M.; Grossman, P.D.; Morning S.E.Anal. Chem. 1993,65, 489A-493A.Google Scholar
  18. [18]
    Moring, S.E.; Reel, R.T.; van Soest, R.E.J.Anal. Chem. 1993,65, 3454–3459.CrossRefGoogle Scholar
  19. [19]
    Liu, S.; Dasgupta, P.K.Anal. Chim. Acta 1993,283, 747–751.CrossRefGoogle Scholar
  20. [20]
    Kim, S. Kim, W., Hahn, J.H.J. Chromatogr. A 1994,680, 109–115.CrossRefGoogle Scholar
  21. [21]
    Xue, Y.; Yeung, E.S.Anal. Chem. 1994,66, 3575–3580.CrossRefGoogle Scholar
  22. [22]
    Dittmann, M.M.; Rozing G.P.; Ross, G.; Adam, T.; Unger K.J. Cap. Elec. 1997,5, 201–212.Google Scholar
  23. [23]
    Vissers, J.P.C.J. Chromatogr. A 1999,856, 117–121.CrossRefGoogle Scholar
  24. [24]
    Ding, J.; Vouros P.Anal. Chem. 1997,69, 379–384.CrossRefGoogle Scholar
  25. [25]
    Stead, D.A.; Reid, R.G.; Taylor, R.B.J. Chromatogr. A. 1998,798, 259–264.CrossRefGoogle Scholar
  26. [26]
    Gort, S.M.; Hogendoorn, E.A.; Dijkman E.; van Zoonen, P.; Hoogerbrugge, R.Chromatographia 1996,42, 17–21.CrossRefGoogle Scholar
  27. [27]
    Mills, M.J.; Maltas, J.; Lough, W.J.J. Chromatogr. A 1997,759, 1–13.CrossRefGoogle Scholar
  28. [28]
    Giddings J.C.Dynamics of Chromatography, Chapter 1, Marcel Dekker, Inc., New York,1965.Google Scholar
  29. [29]
    Jandere, P.; Churacek J.Gradient Elution in Column Liquid Chromatography, Elsevier, Amsterdam, The Netherlands,1985, Chapter 4.Google Scholar
  30. [30]
    Schoenmakers, P.J.; Billiet, H.A.H.; de Galan L.J. Chromatogr. 1979,185, 179–183.CrossRefGoogle Scholar
  31. [31]
    Jiskra, J.; Cramers, C.A.; Byelik, M.; Claessens, H.A.J. Chromatogr. A 1999,862, 121–129.CrossRefGoogle Scholar
  32. [32]
    Inman, E.L.; Tenbarge, H.J.J. Chrom. Sci. 1988,26, 89–93.Google Scholar
  33. [33]
    Altria, K.D.Chromatographia 1993,35, 493–498.CrossRefGoogle Scholar

Copyright information

© Friedr. Vieweg & Sohn Verlagsgesellschaft mbH 2001

Authors and Affiliations

  • M. J. Hilhorst
    • 1
  • G. W. Somsen
    • 1
  • G. J. de Jong
    • 1
  1. 1.Department of Pharmaceutical AnalysisUniversity Centre for PharmacyGroningenThe Netherlands

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