Neutral oligosaccharides are complex in terms of their linkage, either in the linear or branched form. An enormous number of variants are therefore possible. A homopolymer of glucose with a glycosidic bond may assume its stere-ochemical configuration at either the α or β position. Glucose units could be joined through 1,2; 1,3; 1,4; or 1,6 linkages in linear sequence or extended through different linkages, which eventually could lead to a two- or three-dimensional network of homopolymers. Starch and dextran are homopolymer of glucose with α-1,4 and 1, 6 linkages, respectively, and are substantially different in physical and chemical characteristics from the cellulose with the β-1,4 linkage. Because all neutral sugars do not have a charge and seldom contain chromophores, methods for sugar analysis by capillary electrophoresis (CE) are thus limited in separation mechanism as well as detection methods. Sugars do complex well with borate at high pH that provides the charge and yield significant incremental absorbance at 195 nm but still with relatively low molar absorptivity (,). Alternatively, a chemical tag may be introduced to the reducing end of the neutral oligosaccharides to provide enhanced sensitivity and introduce charges to the sugars for electrophoretic separation. The earliest CE-based analysis of derivatized sugars was the reductive amination adducts of sugar with 2-aminopyridine (2-AP). The method was first explored by Honda et al. (,) for high-resolution CE analysis of mono- and oligosaccharides.

Drug discovery can involve screening natural products or synthesizing innovative new compounds, and the process can become more challenging with products that contain one or more chiral centers. These optically active compounds tend to make good drug candidates, however, so they require stereochemically selective assay methods for their analysis. In this article, the authors describe an enantiomer analysis method development strategy that uses a family of highly sulfated cyclodextrins to resolve a diverse array of compounds. They propose this approach as a first step in developing methods for separating enantiomers.

Automation is essential for rapid genetic-based mutation analysis in clinical laboratory to screen a large number of DNA samples. We propose in this report an automatic process using Beckman Coulter P/ACE™ capillary electrophoresis (CE) with laser-induced fluorescence (LIF) system to detect a single-point mutation in the codon 12 of human K-ras gene. Polymerase chain reaction (PCR) using a fluorescently labeled reverse primer and a plain forward primer to specifically amplify a selected 50 bp DNA fragment in human K-ras gene. The amplified DNA is placed on the sample tray of the CE system with a pre-programmed step for single-strand conformation polymorphism (SSCP) analysis. Sample injection and denaturation processes are performed online along with separation and real-time data analysis. The concept of automation for rapid DNA mutation analysis using CE-LIF system for SSCP is presented.

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.