名称:
Characterization of 9-Aminopyrene-1,4,6-trisulfonate Derivatized Sugars by Capillary Electrophoresis with Laser-Induced Fluorescence Detection
摘要:
Mono- and oligosaccharides with reducing ends were derivatized with 9-aminopyrene-1,4,6-trisulfonate (APTS) by reductive amination. The resulting adducts were characterized by capillary electrophoresis (CE) with laser-induced fluorescence (LIF) detection. The APTS-derivatized sugars have significant absorption at 488 nm (35% of its 455 mm maximum absorption), while APTS (lambda(max) = 424 mn) has only 4% of its lambda(max) absorption. When excited at 488 mm, the APTS-derivatized sugars fluoresce at a maximum wavelength of 512 mm, while APTS itself has a much weaker fluorescence with a maximum at 501 nm. By using a 488-nm argon-ion laser for excitation and a narrow band filter at 520 nm for fluorescence emission, the APTS-derivatized sugars can be selectively detected while the signal of the excess APTS reagent is drastically suppressed. The APTS-derivatized monosaccharides were readily separated in borate buffer (pH 10.2), while the oligosaccharide ladders were analyzed using either an acidic phosphate buffer (pH 2.2) or the alkaline borate buffer for separation. The present APTS derivatization chemistry is capable of converting 2 pmol of sugar analyte to the fluorescent derivative detectable by the present CW LIF procedure. The use of CE/LIF as a tool for the investigation of the specificity of enzyme action of glycosidases using an end-labeled oligosacchariae substrate is also demonstrated.