Electrospray Ionization Mass Spectrometric Analysis of Highly Reactive Glycosyl Halides

Attila Bokros,Zoltán Kele,János Szolomájer,Lajos Kovács,Tünde Zita Illyés,Annamária Bánfi,Zoltán Kupihár

doi:10.3390/molecules17078351

Attila Bokros, Zoltán Kele + Show 5 more

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https://doi.org/10.3390/molecules17078351

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Abstract

Highly reactive glycosyl chlorides and bromides have been analysed by a routine mass spectrometric method using electrospray ionization and lithium salt adduct-forming agents in anhydrous acetonitrile solution, providing salient lithiated molecular ions [M+Li]+, [2M+Li]+etc. The role of other adduct-forming salts has also been evaluated. The lithium salt method is useful for accurate mass determination of these highly sensitive compounds.

Highlights

Carbohydrates are the most abundant organic compounds on Earth
Their structures can be seen in Figure 1. 2-Deoxy-3,5-di-O-p-toluoyl- -D-erythro-pentofuranosyl chloride [14] is often used in the synthesis of 2'-deoxynucleosides while 2,3,4,6-tetra-O-acetyl- -D-glucopyranosyl bromide [15] is the most common glycosyl halide
Based on our earlier experience [12], anhydrous acetonitrile was selected as a solvent because it is frequently used in carbohydrate chemistry, compatible with the ESI-MS instruments, the protected glycosyl halides are highly soluble in it, and it can dissolve the required amount of adduct-forming lithium salt

Summary

Introduction

Carbohydrates are the most abundant organic compounds on Earth. Their multifaceted role is underlined, among others, by the extensive and varied glycosylation pattern they display in a number of conjugates (glycoproteins, proteoglycans, glycolipids, glycoproteolipids etc.). The elemental analysis and mass spectrometric characterization of glycosyl halides is greatly hampered by their moisture sensitivity and in the routinely used electrospray mass spectrometry cocktails containing alcohols, water and acids they decompose rapidly, as well as under the high-temperature conditions of harsher ionization techniques (e.g., electron impact). Owing to these difficulties the mass spectrometric characterization of glycosyl halides is very scarce in the literature and is limited to the tandem electrospray mass spectrometric investigation of the relatively stable glycosyl fluorides published in Russian [10,11]. In the present paper we would like to disclose our results on the ESI-MS characterization and accurate mass measurement of selected glycosyl chloride and bromide analytes

Sample Preparation

Measurement of Glycosyl Chloride and Bromide Samples

Accurate Mass Determination

General

Conclusions