Matrix‐assisted ultraviolet laser desorption/ionization time‐of‐flight mass spectrometry of β‐(1 → 3), β‐(1 → 4)‐xylans from Nothogenia fastigiata using nor‐harmane as matrix

Abstract

Three xylan fractions isolated from the red seaweed Nothogenia fastigiata (Nemaliales) were analyzed by ultraviolet matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (UV-MALDI-TOFMS). UV-MALDI-TOFMS was carried out in the linear and reflectron modes, and as routine in the positive and negative ion modes. Of the several matrices tested, nor-harmane was the only effective one giving good spectra in the positive ion mode. The number-average molar masses of two of the fractions, calculated from the distribution profiles, were lower than those determined previously by (1)H NMR analysis, suggesting a decrease in the ionization efficiency with increasing molecular weight; weight-average molar mass and polydispersity index were also determined. As the xylans retained small but significant quantities of calcium salts, the influence of added Ca(2+) as CaCl(2) on UV-MALDI-MS was investigated. The simultaneous addition of sodium chloride and calcium chloride was also analyzed. Addition of sodium chloride did not change the distribution profile of the native sample showing that the inhibitory effect is due to Ca(2+) and not to Cl(-). Addition of calcium chloride with 1:1 analyte/salt molar ratio gave spectra with less efficient desorption/ionization of oligomers; the signals of these oligomers were completely suppressed when the addition of the salt became massive (1:100 analyte/salt molar ratio).

Tandem Mass Spectrometry of Tagged and Permethylated Polysaccharides

“…However, the MALDI process is known to produce predominately singly charged ions. Different matrices have been used for the analysis of pullulans, like 2,5-dihydroxybenzoic acid (Stahl et al, 1991;Garozzo et al, 2000), 2,4,6-trihydroxyacetophenone and nor-harmane (Fukuyama et al, 2005). The use of the ionic liquid matrix like 2,5-dihydroxybenzoic acid butylamine (DHBB) turned out to be well suited for the analysis of pullulan samples in terms of signal intensities of very high mass polymers (Chang et al, 2011b).…”

Structural characterization of native high‐methoxylated pectin using nuclear magnetic resonance spectroscopy and ultraviolet matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. Comparative use of 2,5‐dihydroxybenzoic acid and nor‐harmane as UV‐MALDI matrices

“…have described the application of commercial citrus high‐methoxylated pectin (HMP) in flavour release as an encapsulation matrix 25, 26. As part of an ongoing project on the comparative study of the behaviour of different compounds as UV‐MALDI matrices for carbohydrate analysis,27–32 we conducted a special inter‐laboratory cooperation project on the structural characterization of this HMP. As far as we know, nor ‐harmane has never been used as a UV‐MALDI matrix for the analysis of pectins.…”

Analysis of carbohydrates and glycoconjugates by matrix‐assisted laser desorption/ionization mass spectrometry: An update for the period 2005–2006

“…Because the glycans retain a small amount of calcium, the influence of Ca 2þ was investigated. Added sodium chloride was shown not to change the distribution profile whereas calcium chloride suppressed the signals (Fukuyama et al, 2005). Choi and Ha (2006) report that the relative abundance of the [M þ Na] þ ion from the malto-oligosaccharides containing from three to seven residues increases to a maximum for the hexamer and attribute their findings to the increased chance for sodium bridges to form between adjacent sugar rings for the larger oligomers.…”