Characterization of dissolved organic matter using high-performance liquid chromatography (HPLC)–size exclusion chromatography (SEC) with a multiple wavelength absorbance detector

Abstract

a b s t r a c tHigh-performance liquid chromatography-size exclusion chromatography (HPLC-SEC) coupled with a multiple wavelength absorbance detector (200-445 nm) was used in this study to investigate the apparent molecular weight (AMW) distributions of dissolved organic matter (DOM). Standard DOM, namely humic acid, fulvic acid and hydrophilic acid, from the Suwannee River were tested to ascertain the performance and sensitivity of the method. In addition to four compounds groups: humic substances (Peak 1, AMW 16 kD), fulvic acids (Peak 2, AMW 11 kD), low AMW acids (Peak 3, AMW 5 kD), and low AMW neutral and amphiphilic molecules, proteins and their amino acid building blocks (Peak 4, AMW 3 kD), an new group that appears to include low AMW, 6-10 kD, humic substances was found based on investigating the spectra at various elution times. The spectroscopic parameter S >365 (slope at wavelengths >365 nm) was determined to be a good predictor of the AMW of the DOM. The detector wavelength played an important role in evaluating the AMW distribution. For some fractions, such as the humic and low AMW non-aromatic substances, the error in measurement was ±30% as determined by twodimensional chromatograms detected at an artificially selected wavelength. HPLC-SEC with multiple wavelength absorbance detection was found to be a useful technique for DOM characterization. It characterized the AMW distributions of DOM more accurately and provided additional, potentially important information concerning the properties of DOM with varying AMWs.

A critical review on characterization strategies of organic matter for wastewater and water treatment processes

“…It has been reported that soluble microbial products (SMPs) are the most significant components of DOM in effluents of membrane bioreactors (MBRs) (Jarusutthirak et al, 2002;Romera-Castillo et al, 2014). To date, it has been revealed that molecular properties of DOM, particularly its molecular weight, strongly affect its reactivity in both natural and engineered aquatic systems (Her et al, 2003;Leenheer and Croue, 2003;Shon et al, 2004Shon et al, , 2007Yan et al, 2007Yan et al, , 2012. For this reason, it is possible to use the MW profiles of DOM as a helpful tool to evaluate its treatability in coagulation (Conte and Piccolo, 1999;Yan et al, 2007).…”

Impact of seasonal climate change on optical and molecular properties of river water dissolved organic matter by HPLC-SEC and UV-vis spectroscopy

“…A river with a large catchment area usually receives a considerable amount of soil-derived (usually named allochthonous) organic matter. The DOM, expressed as dissolved organic carbon (DOC) concentration, depends on many hydrological parameters that are highly variable, as noted in recent studies [9,10]. Increases in DOC concentrations in water are evident and observed in many countries, but the reasons are still unclear.…”

“…Milli-Q water served as a blank. [9] were applied for the characterisation of the optical properties.…”

“…Several ratios have been found to serve as proxies for DOM compositional changes. The theoretical background is described in Yan et al's recent work [9].…”

“…High-performance size-exclusion chromatography is extensively used for DOM characterisation and fractionation, because it is a non-destructive technique with well-known advantages [9,11], that has been successfully applied in several studies by the present author [12,13]. Usually, the most common wavelength used to detect separated DOM fractions is 254 nm, but more studies nowadays apply multi-wavelength detection (diode array detection, (DAD)) [14].…”