Capillary zone electrophoresis separation and laser‐based detection of both fluorescein thiohydantoin and dimethylaminoazobenzene thiohydantoin derivatives of amino acids

Abstract

Capillary zone electrophoresis is employed for the separation and analysis of both fluorescein thiohydantoin and dimethylaminoazobenzene thiohydantoin derivatives of amino acids. Detection of minute amounts of these amino acid derivatives is an important milestone in the development of a high sensitivity protein sequencer. Current detection limits for the fluorescein derivative is on the order of 10(-21) moles whereas detection limits for the dimethylaminoazobenzene derivative is on the order of 10(-16) moles.

Analytical Aspects of Amino, Quaternary Ammonium, Nitro, Nitroso and Related Functional Groups

“…Lowering the absolute detection limits of thiohydantoin derivatives of the amino acids is a basic requirement for the development of highly sensitive protein sequencer based on Edman-like processes. Thus, the absolute LOD of thiohydantoin derivatives are at present of the order of 10 16 mol for 141 and 10 21 mol for 133 331 .…”

Capillary electrophoresis

“…A comparison of charge-coupled device (CCD) fluorescence detection photomultiplier tube detection for this instrument was also presented (227). With a laser excitation source and sheat flow detector, limits of detection of approximately 10"20 mol of amino acids labeled with fluorescein isothiocynate were reported (228,229). Low-zeptomole (1 zmol = 10"21 mol) detection limits were also reported for DNA sequencing by capillary gel electrophoresis (230,231).…”

Attomole Determination of Phenyl Thiohydantoin Derivatives of Amino Acids by Capillary Zone Electrophoresis Separation and Ultraviolet-Laser Excited Thermo-Optical Absorbance Detection

“…Although the reagents can be detected with exquisit sensitivity [3], there has been very little application of the modified reagents. It appears that limited reaction efficiency during the formation of the thiocarbamyl has discouraged application of the modified Edman reagents.…”

“…Capillary electrophoresis is a useful technique for the rapid and efficient separation of minute amounts of analyte [3]. Zone electrophoresis has been used to determine phenylthiocarbamyl (PTC) amino acids; ultraviolet absorbance produces detection limits of -0.2 picomoles of PTC amino acids [4].…”