Fluorescence detection in capillary zone electrophoresis using a charge-coupled device with time-delayed integration

Abstract

A fluorescence detection system for capillary zone electrophoresis is described in which a charged-coupled device (CCD) views a 2-cm section of an axially illuminated capillary column. The CCD is operated in two readout modes: a snapshot mode that acquires a series of images in wavelength and capillary position, and a time-delayed integration mode that allows long exposure times of the moving analyte zones. By use of the latter mode, the ability to differentiate a species based on both its fluorescence emission and migration rate is demonstrated for fluorescein and sulforhodamine 101. The detection limit for fluorescein isothiocyanate (FITC) is 1.2 X 10(-20) mol; detection limits for FITC-amino acids are in the (2-8) X 10(-20) mol range.

Capillary electrophoresis of catecholamines with laser‐induced fluorescence intensified charge‐coupled device detection

“…Comparison of FITC and CBQCA as derivatizing agents FITC and CBQCA are two kinds of fluorescent derivatizing agent widely used in CE (Cheng and Dovichi, 1988;Sweedler et al, 1991;Zhang et al, 1991;Liu et al, 1991b;Soini et al, 1994;Bergquist et al, 1994;Arriaga et al, 1995). The former forms a derivative with an excitation maximum at 488 nm, which is coincident with the argon laser, and an emission maximum at 516 nm.…”

“…-10 À21 mol can be reached (Cheng and Dovichi, 1988;Sweedler et al, 1991;Zhang et al, 1991;Ueda et al, 1992), and by the use of derivatization reaction various molecules such as amino acids (Lada and Kennedy, 1996), peptides (Chan et al, 1993), proteins (Lee and Yeung, 1992) and carbohydrates (Liu et al, 1991a) can be detected.…”

“…Cheng et al (1990) first used CCD as a fluorescence detector in CE and obtained a threedimensional electropherogram with wavelength information. Sweedler et al (1991) utilized the time-delayed integration mode to detect subattomole quantity of fluorescein isothiocyanate-labeled amino acids and neuropeptides. The multi-wavelength fluorescence electropherograms detected by CCD were used for rapid DNA sequencing (Karger et al, 1991), purity analysis of fluorescence agents (Xiong et al, 1996b), determination of tryptophan and tyrosine contents of peptides (Timperman et al, 1995), and multicomponent analysis of highly overlapped capillary electrophoretic peaks (Xiong et al, 1996c).…”

Capillary zone electrophoresis of amino acids on a hybrid poly(dimethylsiloxane)-glass chip

“…Amino acids were derivatized with FITC isomer I using the procedure described in [40]. The ratio of amino acid:FITC was 10:1 and 1:1 mol.…”

Effects of injector geometry and sample matrix on injection and sample loading in integrated capillary electrophoresis devices

“…Amino acid samples consisted of a mixture of 10 mM arginine and 10 mM glutamic acid (Sigma, St. Louis, MO), prelabeled with fluorescein isothiocyanate (FITC; Sigma). The labeling procedure has been described previously [12,25]. Final samples were prepared by combining appropriate volumes of stock FITC-Arg and FITC-Glu solutions and diluting with the desired Tris/boric acid/KCl buffer to produce solutions which were 10 mM in each FITC-Arg and FITC-Glu, differing only in ionic strength.…”