Enantioselective micellar electrokinetic chromatography of dl-amino acids using (+)-1-(9-fluorenyl)-ethyl chloroformate derivatization and UV-induced fluorescence detection

Amir Prior, Erik van de Nieuwenhuijzen, Gerhardus J. de Jong, Govert W. Somsen*

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

Chiral analysis of dl-amino acids was achieved by micellar electrokinetic chromatography coupled with UV-excited fluorescence detection. The fluorescent reagent (+)-1-(9-fluorenyl)ethyl chloroformate was employed as chiral amino acid derivatizing agent and sodium dodecyl sulfate served as pseudo-stationary phase for separating the formed amino acid diastereomers. Sensitive analysis of (+)-1-(9-fluorenyl)ethyl chloroformate-amino acids was achieved applying a xenon-mercury lamp for ultraviolet excitation, and a spectrograph and charge-coupled device for wavelength-resolved emission detection. Applying signal integration over a 30 nm emission wavelength interval, signal-to-noise ratios for derivatized amino acids were up to 23 times higher as obtained using a standard photomultiplier for detection. The background electrolyte composition (electrolyte, pH, sodium dodecyl sulfate concentration, and organic solvent) was studied in order to attain optimal chemo- and enantioseparation. Enantioseparation of 12 proteinogenic dl-amino acids was achieved with chiral resolutions between 1.2 and 7.9, and detection limits for most derivatized amino acids in the 13–60 nM range (injected concentration). Linearity (coefficients of determination > 0.985) and peak-area and migration-time repeatabilities (relative standard deviations lower than 2.6 and 1.9%, respectively) were satisfactory. The employed fluorescence detection system provided up to 100-times better signal-to-noise ratios for (+)-1-(9-fluorenyl)ethyl chloroformate-amino acids than ultraviolet absorbance detection, showing good potential for d-amino acid analysis.

Original languageEnglish
Pages (from-to)2983-2992
Number of pages10
JournalJournal of Separation Science
Volume41
Issue number14
Early online date22 May 2018
DOIs
Publication statusPublished - Jul 2018

Funding

This work was financially supported by the Netherlands Organization for Scientific Research (ECHO project 711.011.003).

FundersFunder number
Netherlands Organization for Scientific Research
Nederlandse Organisatie voor Wetenschappelijk Onderzoek711.011.003

    Keywords

    • amino acids
    • chiral separation
    • derivatization
    • fluorescence detection
    • micellar electrokinetic chromatography

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