Mass Spectrometry Approach for Differentiation of Positional Isomers of Saccharides: Toward Direct Analysis of Rare Sugars

Abstract

Rare sugars have gained popularity in recent years due to their use in antiaging treatments, their ability to sweeten with few calories, and their ability to heal infections. Rare sugars are found in small quantities in nature, and they exist typically as isomeric forms of traditional sugars, rendering some challenges in their isolation, synthesis, and characterization. In this work, we present the first direct mass spectrometric approach for differentiating structural isomers of sucrose that differ only by their glycosidic linkages. The method employed a noncontact nanoelectrospray (nESI) platform capable of analyzing minuscule volumes (5 μL) of saccharides via the formation of halide adducts ([M+X]−; X = Cl and Br). Tandem mass spectrometry analysis of the five structural isomers of sucrose afforded diagnostic fragment ions that can be used to distinguish each isomer. Detailed mechanisms showcasing the distinct fragmentation pattern for each isomer are discussed. The method was applied to characterize and confirm the presence of all five selected rare sugars in raw honey complex samples. Aside from the five natural α isomers of sucrose, the method was also suitable for differentiating some β isomers of the same glycosidic linkages, provided the monomeric sugar units are different. The halide adduct formation via the noncontact nESI source was also proven to be effective for oligosaccharides such as raffinose, β-cyclodextrin, and maltoheptaose. The results from this study encourage the future development of methods that function with simple operation to enable straightforward characterization of small quantities of rare sugars.

Two-dimensional isomer differentiation using liquid chromatography-tandem mass spectrometry with in-source, droplet-based derivatization

“…To avoid distribution of saccharide signal into monosubstituted precursor (M/PBA) and hydroxylated species (M/PBA + OH), we are exploring other reactions in parallel studies. 65…”

“…Its wide availability and relative ease of production makes it the most prevalent sweetener in the food industry. 65 However, excess sucrose consumption can lead to health problems including tooth decay, obesity, high blood pressure, cardiovascular disease, and type 2 diabetes. Consequently, there is a need to identify, characterize, and market alternative sweeteners that have the same effect on the consumer palette but mitigate the health challenges associated with high sugar intake.…”

Multi Analyte Concentration Analysis of Marine Samples Through Regression Based Machine Learning

“…Glucose chloride adduct formation was assisted via addition of 10 mM ammonium chloride. 36 Mass spectra were recorded using a Thermo Fisher Scientific Finnigan ion trap mass spectrometer (San Jose, CA). All MS parameters were held constant throughout with 3 microscans and 100 ms injection time.…”

An improved algorithm for resolving overlapping peaks in ion mobility spectrometry and its application to the separation of glycan isomers

“…Therefore, the accurate resolution of glycan isomers holds crucial significance in gaining a deeper understanding of the biological functions of glycans. 4,5…”

“…Therefore, the accurate resolution of glycan isomers holds crucial significance in gaining a deeper understanding of the biological functions of glycans. 4,5 Currently, a number of techniques are available to characterize glycan isomers. 6 Nuclear magnetic resonance 7,8 requires a large amount of pure samples and is time-consuming in nature, posing limitations on its application.…”