Glycans quantitative analysis

Ultraviolet and visible Absorption of UV and visible radiation leading to electronic excitation N, P Ligand binding sites, side chain exposure, environment. Apphcable to proteins and nucleic acids but not glycans. Quantitative analysis. DNA conformation. Anneahng and hybridization studies of nucleic acids. 

D. J. Harvey, L. Royle, C. Radcliffe, P. M. Rudd, and R. A. Dwek, Stractural and quantitative analysis of N-linked glycans by matrix-assisted laser desorption ionization and negative ion nanospray mass spectrometry. Anal. Biochem., 376 (2008) 44-60. 

AA-Ac labeled glycans also give excellent results in MALDI-MS and on current ion-trap instruments detailed MS" studies can be performed with sub-picomole samples. The combination of this analysis with fractionation of complex samples on EIR or amide HPLC is particularly useful allowing reliable quantitation of the AA-Ac tagged glycans by HPLC and detailed structural characterization by MS" fragmentation. 

An additional type of derivative that is often used for glycan profiling and analysis is the modification of the reducing end with a chromophore, usually achieved by the formation of a Schiff base with an aromatic amine, and subsequent reduction with sodium borohydride to stabilize the initially formed product by its conversion to a saturated amine. This procedure was initially developed for HPLC analysis with ultraviolet detection, but it is also appropriate for MS analysis because the substituted amino group represents a site for charge localization that simplifies the fragmentation pattern and also provides the opportunity to introduce a stable isotope label for quantitative purposes (54). 

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