SYMPOSIA PAPER Published: 01 January 1990

Subattomole Amino Acid Analysis by Laser-Induced Fluorescence: The Sheath Flow Cuvette Meets Capillary Zone Electrophoresis


Subattomole analysis of fluorescein isothiocyanate (FITC) derivatives of amino acids is produced by combining capillary zone electrophoresis for high-efficiency separation with laser-induced fluorescence for high sensitivity detection. To optimize the separation process, several buffer systems were investigated. A pH 10 carbonate buffer provided good separation of 14 FITC amino acids. Concentration detection limits range from 5 × 10-12 M for alanine to 9 × 10-11 M for lysine, injected onto the column; ∼9 × 10-21 mol of alanine is contained within the ∼1-nL injection volume at the detection limit. The alanine detection limit corresponds to less than 6000 molecules injected onto the column and represents a four order of magnitude improvement in the state of the art for fluorescent detection of amino acids and a six order of magnitude improvement in the state of the art for the detection limit for isothiocyanate derivatives of amino acids.

Author Information

Cheng, YF
University of Alberta, Edmonton, Alberta, Canada
Dovichi, NJ
University of Alberta, Edmonton, Alberta, Canada
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Developed by Committee: E13
Pages: 151–159
DOI: 10.1520/STP23488S
ISBN-EB: 978-0-8031-5127-7
ISBN-13: 978-0-8031-1455-5