Analytical methods for the determination of sugars in marine samples: A historical perspective and future directions

Abstract

Analytical techniques employed over the past three decades for sugar determination in marine samples are reviewed. This review first summarizes the different hydrolysis protocols used by marine biogeochemists to extract sugars from various marine matrices including sinking particulate organic matter (POM), dissolved organic matter (DOM), ultrafiltrated dissolved organic matter (UDOM), and sediments. The most commonly used methods for total sugar estimation are phenol sulfuric acid (PSA), 3‐methyl‐2‐benzo thiazoline hydrazone hydrochloride (MBTH), and 2,4,6‐tripyridyl‐s‐triazine (TPTZ). For individual sugars, gas chromatographyflame ionization detection (GC‐FID), liquid chromatography‐borate complexes (LC), high performance liquid chromatography‐ethylenediamine derivatives (HPLC‐EDA), high performance liquid chromatography‐p‐aminobenzoic acid derivatives (HPLC‐p‐AMBA), and high performance anion exchange chromatography‐pulsed amperometric detection (HPAEC‐PAD) have been employed, the last method being the most widely used. This study demonstrated that mild and strong hydrolysis give comparable results for open ocean samples, including POM, DOM, and UDOM (except for sediments) using chromatographic or colorimetric techniques. A survey of 130 sugar data sets revealed that more than half of the sugar‐C escapes analysis using chromatographic or colorimetric techniques compared to 1H and 13C NMR techniques. The reconciliation of the NMR and colorimetric or chromatographic measurements is likely to be the key to the understanding of the composition of DOM. This study also demonstrated that most of the published sugar data obtained by chromatographic techniques are related to suspended or sinking POM and sediments, and that there is a need for data on sugar composition in DOM and UDOM, which involve further analytical difficulties for chromatographic analysis.

Revealing structural properties of the marine nanolayer from vibrational sum frequency generation spectra

“…More classical techniques have constantly improved just as well. For example, advanced colorimetric and chromatographic protocols are available to determine the molecular composition of polysaccharides and, in the near future, biochemical methods could be adapted to marine samples in order to investigate the corresponding secondary and tertiary structures [Panagiotopoulos and Sempéré, 2005].…”

Saccharides enhance iron bioavailability to Southern Ocean phytoplankton

“…Gluconic and domoic acids both form weak iron complexes that fall within the L2 class (log K Fe′L 8.7 and 8.8 M −1 , respectively) (17,20). Unlike siderophores, reported at picomolar levels (21), saccharides occur in relatively high concentrations in surface waters (nanomolar to micromolar) (22), giving them the potential to outcompete the L1 class for iron binding-a critical step toward defining iron bioavailability (20). Saccharides represent 3-50% of dissolved and colloidal organic matter (18,23,24) and are typically present at 0.2-500 nM in the Pacific Ocean (22), representing up to 20-30 μM of carbon (23).…”

“…Unlike siderophores, reported at picomolar levels (21), saccharides occur in relatively high concentrations in surface waters (nanomolar to micromolar) (22), giving them the potential to outcompete the L1 class for iron binding-a critical step toward defining iron bioavailability (20). Saccharides represent 3-50% of dissolved and colloidal organic matter (18,23,24) and are typically present at 0.2-500 nM in the Pacific Ocean (22), representing up to 20-30 μM of carbon (23). Polysaccharides are more abundant than monosaccharides in surface water, comprising up to 70% of total saccharides (23).…”

Characterization of methyl sugars, 3-deoxysugars and methyl deoxysugars in marine high molecular weight dissolved organic matter

“…Lipids represent < 2% HMWDOC (Mannino and Harvey, 1999;Wang et al, 2004). It is notable that the distribution of major sugars released by acid hydrolysis of HMWDOM is nearly the same irrespective of where the sample was collected or the specific hydrolysis conditions used for depolymerization (Sakugawa and Handa, 1985;McCarthy et al, 1996;Aluwihare et al, 1997;Borch and Kirchman, 1997;Panagiotopoulos and Sempéré, 2005). Most of the carbohydrate in HMWDOM is therefore not characterized by conventional HPLC or GC techniques.…”

“…However, after acid hydrolysis, only 10-20% of HMWDOM carbon (HMWDOC) can be recovered as simple neutral sugars (arabinose (I), fucose (II), galactose (III), glucose (IV), mannose (V), rhamnose (VI) and xylose (VII); see Appendix 1) using gas or high pressure liquid chromatography (GC, HPLC; Panagiotopoulos and Sempéré, 2005 and references therein). Another 5-8% of HMWDOC is recovered as acetic acid (Aluwihare et al, 1997), and a further 3-5% of HMWDOC is recovered as amino acids (McCarthy et al, 1996).…”