scholarly journals A protocol for quantifying mono- and polysaccharides in seawater and related saline matrices by electro-dialysis (ED) – combined with HPAEC-PAD

Ocean Science ◽  
2020 ◽  
Vol 16 (4) ◽  
pp. 817-830
Author(s):  
Sebastian Zeppenfeld ◽  
Manuela van Pinxteren ◽  
Anja Engel ◽  
Hartmut Herrmann
Keyword(s):  
High Performance ◽  
Ice Core ◽  
Amperometric Detection ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Amino Sugars ◽  
Uronic Acids ◽  
Field Samples ◽  
Arctic Ice ◽  
Seawater Samples

Abstract. An optimized method is presented to determine dissolved free (DFCHO) and dissolved combined carbohydrates (DCCHO) in saline matrices, such as oceanic seawater, Arctic ice core samples or brine using a combination of a desalination with electro-dialysis (ED) and high-performance anion exchange chromatography coupled to pulsed amperometric detection (HPAEC-PAD). Free neutral sugars, such as glucose and galactose, were found with 95 %–98 % recovery rates. Free amino sugars and free uronic acids were strongly depleted during ED at pH=8, but an adjustment of the pH could result in higher recoveries (58 %–59 % for amino sugars at pH=11; 45 %–49 % for uronic acids at pH=1.5). The applicability of this method for the analysis of DCCHO was evaluated with standard solutions and seawater samples compared with another established desalination method using membrane dialysis. DFCHO in field samples from different regions on Earth ranged between 11 and 118 nM and DCCHO between 260 and 1410 nM. This novel method has the potential to contribute to a better understanding of biogeochemical processes in the oceans and sea–air transfer processes of organic matter into the atmosphere in future studies.

scholarly journals A protocol for quantifying mono- and polysaccharides in seawater and related saline matrices by electro-dialysis (ED) – combined to HPAEC-PAD

2020 ◽  
Author(s):  
Sebastian Zeppenfeld ◽  
Manuela van Pinxteren ◽  
Anja Engel ◽  
Hartmut Herrmann
Keyword(s):  
High Performance ◽  
Ice Core ◽  
Amperometric Detection ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Real Field ◽  
Amino Sugars ◽  
Uronic Acids ◽  
Field Samples ◽  
Arctic Ice

Abstract. An optimized method is presented to determine free (DFCHO) and combined monosaccharides (CCHO) in saline matrices, such as oceanic seawater, Arctic ice core samples or brine using a combination between desalination with electro-dialysis and high performance anion exchange chromatography coupled to pulsed amperometric detection (HPAEC-PAD). Free neutral sugars, such as glucose and galactose, were found with 95–98 % recovery rates. Free amino sugars and uronic acids were strongly depleted during electro-dialysis at pH = 8, but an adjustment of the pH could result in higher recoveries (58–59 % for amino sugars at pH = 11; 45–49 % for uronic acids at pH = 1.5). The applicability of this method for the analysis of CCHO was evaluated with standard solution and real seawater samples compared with another established desalination method using membrane dialysis. DFCHO in real field samples from different regions on earth ranged between 11–118 nM and CCHO between 260–1410 nM. This novel method potentially contributes to a better understanding of biogeochemical processes in the oceans and sea-air transfer processes of organic matter into the atmosphere during further research studies.

scholarly journals Enzymatic Synthesis and Characterization of Different Families of Chitooligosaccharides and Their Bioactive Properties

2021 ◽  
Vol 11 (7) ◽  
pp. 3212
Author(s):  
Noa Miguez ◽  
Peter Kidibule ◽  
Paloma Santos-Moriano ◽  
Antonio O. Ballesteros ◽  
Maria Fernandez-Lobato ◽  
...  
Keyword(s):  
High Performance ◽  
Chemical Characterization ◽  
Amperometric Detection ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Enzymatic Production ◽  
Bioactive Properties ◽  
Substrate Properties ◽  
Chitin Hydrolysis

Chitooligosaccharides (COS) are homo- or hetero-oligomers of D-glucosamine (GlcN) and N-acetyl-D-glucosamine (GlcNAc) that can be obtained by chitosan or chitin hydrolysis. Their enzymatic production is preferred over other methodologies (physical, chemical, etc.) due to the mild conditions required, the fewer amounts of waste and its efficiency to control product composition. By properly selecting the enzyme (chitinase, chitosanase or nonspecific enzymes) and the substrate properties (degree of deacetylation, molecular weight, etc.), it is possible to direct the synthesis towards any of the three COS types: fully acetylated (faCOS), partially acetylated (paCOS) and fully deacetylated (fdCOS). In this article, we review the main strategies to steer the COS production towards a specific group. The chemical characterization of COS by advanced techniques, e.g., high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) and MALDI-TOF mass spectrometry, is critical for structure–function studies. The scaling of processes to synthesize specific COS mixtures is difficult due to the low solubility of chitin/chitosan, the heterogeneity of the reaction mixtures, and high amounts of salts. Enzyme immobilization can help to minimize such hurdles. The main bioactive properties of COS are herein reviewed. Finally, the anti-inflammatory activity of three COS mixtures was assayed in murine macrophages after stimulation with lipopolysaccharides.

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