Chromatographic methods for the isolation, separation and characterisation of dissolved organic matter

Abstract

This review presents an overview of the separation techniques applied to the complex challenge of dissolved organic matter characterisation. The review discusses methods for isolation of dissolved organic matter from natural waters, and the range of separation techniques used to further fractionate this complex material. The review covers both liquid and gas chromatographic techniques, in their various modes, and electrophoretic based approaches. For each, the challenges that the separation and fractionation of such an immensely complex sample poses is critically reviewed.

Proposed Guidelines for Solid Phase Extraction of Suwannee River Dissolved Organic Matter

“…This putative selectivity of the PPL sorbent toward hydrophobic and low-molecular-weight molecules in DOM has been previously reported. 30,42 Comparing Suw-water with Suw-RO, aliphatics and olefins were depleted in Suw-RO, whereas CRAM and, in particular, carbohydrates and some methoxy groups (OCH 3 ) were more abundant in Suw-RO. Interestingly, common aromatic molecules (δ H = 6.7−7.8 ppm) were also more abundant in Suw-RO than in Suw-water, with no obvious discrimination of electron-donating (δ H < 7 ppm), electronneutral (δ H = 7.0−7.3 ppm), and electron-withdrawing (δ H > 7.3 ppm) substituents.…”

Solid-phase extraction-stepwise elution (SPE-SE) procedure for isolation of dissolved organic matter prior to ESI-FT-ICR-MS analysis

“…In the past decades, various techniques including spectroscopic, chromatographic and mass spectrometric methods have been established to investigate the composition and characteristics of DOM. These techniques can provide some bulk information such as elemental composition, apparent molecular weight, and the characteristic functional group distribution of DOM [6,8,9]. However, characterization of DOM components at the molecular level remains a challenge due to their highly complex and heterogeneous natures [10,11].…”

Photochemical Generation of Methyl Chloride from Humic Aicd: Impacts of Precursor Concentration, Solution pH, Solution Salinity and Ferric Ion

“…According to Moore [9,17] and Yang et al [18], the methoxy group in simple lignin-like molecules can be the source of the methyl group in CH 3 Cl produced by a photochemical reaction. HA is a complex mixture partially deriving from the lignin structures of higher terrestrial plants [11] and consequently contains syringyl and guaiacyl lignin groups. The FTIR spectrum of HA ( Figure 6) shows the following characteristics: -OH stretching vibration absorption (ν O-H ) at 3700-2700 cm −1 , C-H stretching vibration absorption of aliphatic series (ν C-H ) at 2923/2851 cm −1 , carbonyl C=O absorption (ν C=O ) around 1563 cm −1 , bending vibration of alcohols or carboxylic acids (δ O-H ) and stretching vibration of phenols (ν C-O ) around 1369 cm −1 ; C-O stretching vibration of alcohols, ethers, phenol, and/or polysaccharides around 1100-1200 cm −1 [30,31].…”

“…It is supposed that a component of light absorbing molecules, such as marine colored dissolved organic material (CDOM), takes part in the formation of methyl halides. Dissolved organic matter (DOM) in estuaries and coastal areas is a class of natural organic compounds containing molecules derived from biota in terrestrial (allochthonous) and/or marine (autochthonous) ecosystems [10], which contains a large assemblage of complex chemical structures of polyphenols, carboxyls, methoxyls, quinones, carbohydrates and peptide functionalities [11]. As a complex macromolecular mixture, DOM can absorb light energy and induce photochemical reactions.…”