Characterization Of Natural Organic Matter Research Articles

The application of HPLC–SEC for the simultaneous characterization of NOM and nitrate in well waters

The usefulness of HPLC–SEC for the characterization of well water quality and the identification of surface-water or wastewater percolation into wells was studied. In total, 267 private wells from rural areas of Finland, two surface waters and two wastewater effluents were analyzed for organic matter (Dissolved Organic Carbon (DOC)) and nitrate with conventional methods. High Performance Liquid Size Exclusion Chromatography (HPLC–SEC) was also used for NOM (Natural Organic Matter) and nitrate analysis. High DOC values were found occasionally in both shallow and deep wells. HPLC–SEC with UV-254 detection separated 6 fractions in the wells studied: three High Molecular Weight (HMW) fractions, two Intermediate Molecular Weight (IMW) fractions and a Low Molecular Weight (LMW) fraction. The LMW fraction is an overlap of LMW organic compounds and nitrate. In wells with a high DOC content the chromatograms were typically “surface water”-like, with HMW fractions clearly present and often dominant. Anthropogenic influence on wells was seen in the increase of LMW fraction VI, which shows an increased nitrate concentration. Nitrate concentration can be determined with precision by HPLC–SEC using UV detection at 224 nm.

NOM characterization and removal at six Southern African water treatment plants

Abstract. Organic pollution is a major concern during drinking water treatment. Major challenges attributed to organic pollution include the proliferation of pathogenic micro-organisms, prevalence of toxic and physiologically disruptive organic micro-pollutants, and quality deterioration in water distribution systems. A major component of organic pollution is natural organic matter (NOM). The operational mechanisms of most unit processes are well understood. However, their interaction with NOM is still the subject of scientific research. This paper takes the form of a meta-study to capture some of the experiences with NOM monitoring and analysis at a number of Southern African Water Treatment Plants. It is written from the perspective of practical process selection, to try and coax some pointers from the available data for the design of more detailed pilot work. NOM was tracked at six water treatment plants using dissolved organic carbon (DOC) measurements. Fractionation of the DOC based on biodegradability and molecular weight distribution was done at a water treatment plant in Namibia. A third fractionation technique using ion exchange resins was used to assess the impact of ozonation on DOC. DOC measurements alone did not give much insight into NOM evolution through the treatment train. The more detailed characterization techniques showed that different unit processes preferentially remove different NOM fractions. Therefore these techniques provide better information for process design and optimisation than the DOC measurement which is routinely done during full scale operation at these water treatment plants.

The use of MSSV pyrolysis to assist the molecular characterisation of aquatic natural organic matter

Microscale sealed vessel pyrolysis (MSSVpy) with online gas chromatography mass spectrometry (GC–MS) was used with several other established and complementary analytical methods to robustly characterize the structure of aquatic natural organic matter (NOM) and to practically assess the analytical value of MSSVpy. The NOM used in the study was from North Pine (NP) reservoir, which is one of the major source waters supplying Brisbane, the capital city of the Australian state of Queensland. The reservoir has moderate dissolved organic carbon (DOC; 5 mg L −1) levels and is impacted by algae which periodically occur in bloom proportions. The hydrophobic (HPO; 65% initial DOC) and transphilic (TPI; 12%) fractions showed H/C values >1, low UV abs and low aryl-C measured by NMR which are all indicative of low aromaticity. MSSVpy produced distinctly higher product concentrations than traditional flash pyrolysis and the molecular profile of the HPO and TPI fractions revealed by MSSVpy was correlated with the other analytical data to help establish their structural relevance. Prolific distributions of alkyl substituted aromatic (e.g., benzenes, naphthalenes) and hydroaromatic (e.g., tetralins) products detected in the HPO fraction were attributed to the aromatisation of terpanes and other aliphatic compounds from algal, and possibly also plant sources. Alkyl phenols also detected in HPO in high abundance, are probably from algal biopolymers, but may also reflect a contribution from non-methoxylated lignin units of catchment grasses. There was no analytical evidence of the dihydroxy or methoxy aromatic structures typical of wood lignin or tannin. N-organic pyrolysates (e.g., alkyl pyrroles, pyridines, indoles) of diagenetically altered proteins were concentrated in the TPI fraction. The quantitative importance of the N-organic moiety of the TPI fraction was corroborated by a low C/N ratio and distinctive amide and amine signals detected by 13C NMR and FTIR. This integrated study demonstrates that the qualitative speciation provided by MSSVpy can make a significant contribution to the structural characterisation and source recognition of aquatic NOM.

Constant Current Chronopotentiometric Stripping Analysis of ‘N‐Catalyst’ in Sodium Chloride Solution and Seawater

AbstractCatalytic properties and surface activity of nitrogen containing polymeric organic material (N‐POM) were analyzed by constant current chronopotentiometric stripping analysis (CPSA) and alternating current (AC) voltammetry in sodium chloride solution (pH 8) and seawater. CPSA proved to be a suitable method for determination of low concentrations of N‐POM in seawater by measuring its ‘presodium’ catalytic peak H. A protein human serum albumin (HSA) (15% of N) was used as a model compound and the concentration of N‐POM from natural seawater samples was expressed in HSA concentration equivalents. Peak H represents an additional parameter for characterization of natural organic matter.

Non‐disturbing characterization of natural organic matter (NOM) contained in clay rock pore water by mass spectrometry using electrospray and atmospheric pressure chemical ionization modes

We have investigated the composition of the mobile natural organic matter (NOM) present in Callovo-Oxfodian pore water using electrospray ionization mass spectrometry (ESI-MS), atmospheric pressure chemical ionization mass spectrometry (APCI-MS) and emission-excitation matrix (EEM) spectroscopy. The generation of knowledge of the composition, structure and size of mobile NOM is necessary if one wants to understand the interactions of these compounds with heavy metals/radionuclides, in the context of environmental studies, and particularly how the mobility of these trace elements is affected by mobile NOM. The proposed methodology is very sensitive in unambiguously identifying the in situ composition of dissolved NOM in water even at very low NOM concentration, due to innovative non-disturbing water sampling and ionization (ESI/APCI-MS) techniques. It was possible to analyze a quite exhaustive inventory of the small organic compounds of clay pore water without proceeding to any chemical treatment at naturally occurring concentration levels. The structural features observed were mainly acidic compounds and fatty acids as well as aldehydes and amino acids.

Characterization of NOM in a drinking water treatment process train with no disinfectant residual

For drinking water treatment plants that do not use disinfectant residual in the distribution system, it is important to limit availability of easily biodegradable natural organic matter (NOM) fractions which could enhance bacterial regrowth in the distribution system. This can be achieved by optimising the removal of those fractions of interest during treatment; however, this requires a better understanding of the physical and chemical properties of these NOM components. Fluorescence excitation-emission matrix (EEM) and liquid chromatography with online organic carbon detection (LC-OCD) were used to characterize NOM in water samples from one of the two water treatment plants serving Amsterdam, The Netherlands. No disinfectant residual is applied in the distribution system. Fluorescence EEM and LC-OCD were used to track NOM fractions. Whereas fluorescence EEM shows the reduction of humic-like as well as protein-like fluorescence signatures, LC-OCD was able to quantify the changes in dissolved organic carbon (DOC) concentrations of five NOM fractions: humic substances, building blocks (hydrolysates of humics), biopolymers, low molecular weight acids and neutrals.

Influence of HCl/HF treatment on organic matter in aquifer sediments: A Rock-Eval pyrolysis study

Rock–Eval pyrolysis is increasingly used for the routine characterization of natural organic matter in soils and sediments. In this work the bulk composition of sedimentary organic matter (SOM) in sandy aquifer sediments is studied, as well as purified samples (isolation of SOM) by HCl/HF treatment. This treatment is necessary to avoid detection limit problems for samples with low SOM contents, but the results presented here indicate that this treatment influences the organic geochemistry of the aquifer sediment samples. The FID and CO2/CO pyrograms show a shift of 10–40 °C of the major peak to a lower temperature. Organic matter alteration or removal of components containing O-bearing groups may explain this. It is also suggested that destruction of the mineral matrix may lead to the reduced retention of the material. For the change of the CO2/CO pyrograms of the RC fraction only organic matter alteration seems to be likely. Concentrated organic matter samples may also accelerate the release of exothermic energy and influence the pyrograms. Results indicate that the organic matter concentration in the sample influences the measured total organic matter (TOM) content and the Tmax of the FID pyrogram, while the sample loading (absolute organic matter amount) up to 80 mg in the Rock–Eval apparatus does not. The FID pyrograms can be deconvoluted into four subpeaks, which allows comparison of samples at various depths. Rock–Eval pyrolysis may only be routinely applied to characterize SOM in aquifer sediments when such systematic and analytical phenomena are taken into account.

Interactions of Aqueous NOM with Nanoscale TiO2: Implications for Ceramic Membrane Filtration-Ozonation Hybrid Process

The combined effect of pH and calcium on the interactions of nonozonated and ozonated natural organic matter (NOM) with nanoscale TiO2 was investigated. The approach included characterization of TiO2 nanoparticles and NOM, extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) modeling of NOM-TiO2 and NOM-NOM interactions, batch study on the NOM adsorption onto TiO2 surface, and bench-scale study on the treatment of NOM-containing feed waters using a hybrid process that combines ozonation and ultrafiltration with a 5 kDa ceramic (TiO2 surface) membrane. It was demonstrated that depending on pH and TiO2 loading, the adsorption of NOM species is controlled by either the availability of divalent cations or by preozonation of NOM. XDLVO surface energy analysis predicts NOM adsorption onto TiO2 in the ozone-controlled regime but not in the calcium-controlled regime. In both regimes, short-range NOM-NOM and NOM-TiO2 interactions were governed by acid-base and van der Waals forces, whereas the role of electrostatic forces was relatively insignificant. Ozonation increased the surface energy of NOM, contributing to the hydrophilic repulsion component of the NOM-NOM and NOM-TiO2 interactions. In the calcium-controlled regime, neither NOM-TiO2 nor NOM-NOM interaction controlled adsorption. Non-XDLVO interactions such as intermolecular bridging by calcium were hypothesized to be responsible for the observed adsorption behavior. Adsorption data proved to be highly predictive of the permeate flux performance.

Optimizing treatment for reduction of disinfection by-product (DBP) formation

Recent studies in communities in greater Cairo, Egypt have identified trihalomethanes (THMs) and haloacetic acids (HAAs) at levels that exceed regulatory limits depending upon the season. The objective of this study was to better understand the formation of DBPs in Nile River source water with a view toward optimizing conventional treatment, focusing on enhanced coagulation, to achieve reduction in DBP formation potential (FP) in a cost-effective scheme. To this end, characterisation of natural organic matter (NOM) in Nile raw water and after treatment by fractionating according to hydrophobic-hydrophilic properties was included in the analysis. Seasonal variations in raw water quality were found to be important for achieving optimum reduction of turbidity and DBP formation. In summer, alkalinity is lower; therefore, enhanced coagulation with 30 mg/L alum can be done at pH 6 without excessive additions of acid, and satisfactory reductions in turbidity and DBPs attained. During the remainder of the year, high alkalinity results in enhanced coagulation at about pH 6.5 and notably lower reduction of NOM, THMFP, and HAAs versus summer conditions. Supplementing enhanced coagulation with 10 mg/L PAC is highly recommended for these conditions as it improves removal of all DBP indicators. The transphilic fraction was the main contributor to DBP formation and the primary fraction removed by enhanced coagulation for achieving gains in THMFP reduction.

Characterisation of natural organic matter (NOM) removed by magnetic ion exchange resin (MIEX® Resin)

The aim of the research presented in this paper was to gain greater insight into the characteristics of NOM removed by MIEX® Resin. Previous studies have shown that MIEX® Resin increases the level of removable DOC when used in combination with coagulation, suggesting that these two processes target a different type of organics. Initially the characteristics of DOC in regenerant solutions from four different MIEX® Resin treatment plants were analysed and compared to DOC in the respective raw water. Following this the raw water and the regenerant solutions were coagulated and the characteristics of the residual DOC analysed and compared to the regenerant solutions prior to coagulation. From the regenerant solutions it was seen that MIEX® Resin targets DOC of increased UV254 absorbance, increased charge density and of mid to low molecular weight (5 to 2 kDa). In terms of hydrophobicity no preference of MIEX® Resin for a specific NOM type was seen. The presence of hydrophilic neutral acids in the regenerant solution was unexpected since the removal of only highly charged organic species was expected. Charge density measurements however revealed the presence of functional groups, allowing hydrophilic neutrals to be removed by anion exchange. Comparative coagulation of the raw water and regenerant solution showed that both a residual DOC of similar hydrophobicity in the sub 3 kDa area. Considering that this DOC fraction was present in the regenerant it was concluded that MIEX® Resin removes organics recalcitrant to coagulation from raw water and therefore increases DOC removal when both methods are combined.

Application of a novel polarity method for the characterization of natural organic matter during water treatment

The changes in polarity of natural organic matter (NOM) across a pilot-scale conventional water treatment plant with pre-ozonation and biofiltration were analyzed using the polarity rapid assessment method (PRAM). PRAM is a novel method developed for the characterization of the polarity of NOM in environmental samples. Characterization was accomplished by monitoring UV absorbance (UVA) at 254 nm. Under ambient conditions, the NOM was characterized as highly anionic (>50%), with limited hydrophobic (10―25%) and hydrophilic (0―10%) domains. Results showed temporal variations in the polarity of NOM entering the pilot plant. These differences were ascribed to changes in water blend and variability in NOM characteristics. Changes in NOM chemistry were also observed as the organics passed through the treatment process. Ozonation decreased the hydrophobicity and increased the polarity of NOM , confirming results from previous research utilizing resin fractionation methods. Coagulation, flocculation and biofiltration resulted in the decrease of the hydrophobic and hydrophilic character of the chromophoric NOM. However, these polarity changes varied during the pilot plant run, suggesting a more precise evaluation of NOM through unit operations is warranted.

An urban water cycle perspective of natural organic matter (NOM): NOM in drinking water, wastewater effluent, storm water, and seawater

Natural organic matter (NOM) occurs throughout the hydrologic cycle, varying in both amount and character. In this paper, a description of NOM in surface and drinking water, in groundwater and in seawater is presented. Water samples representing these environments were collected and characterized using multiple NOM characterization techniques, including fluorescence excitation emission matrices (F-EEM) and size exclusion liquid chromatography with organic carbon detection (LC-OCD). The results show that the raw surface water as well as the treated water comprises mainly (>70%) of humic substances. The biopolymers, which are more readily biodegradable, contribute up to 2% of the NOM in the raw water but this is completely removed after treatment. For sea water samples, humic substances represent about 50% of the dissolved organic carbon concentration (DOC), while the fraction with size bigger than 20 kDa (biopolymers) represents about 7%. During soil passage, there was preferential removal of non-humic substances (i.e., biopolymers) from wastewater effluent-impacted surface water while the specific ultraviolet absorbance (SUVA), which reflects the aromatic characteristics of organics in a sample, showed an increasing trend along the depth of the soil column. This is a consequence of the removal of non-humic substances (biopolymers) which results in an increase in aromaticity.

Size-exclusion chromatography with organic carbon detection using a mass spectrometer

A novel organic carbon detector for size-exclusion chromatography (SEC) is described. The instrument uses the conventional UV-persulfate oxidation method to convert organic carbon to CO 2, which is then detected using a mass spectrometer. This system, using the mass spectrometer, had lower limits of detection (LOD) and limits of quantification (LOQ) than a previously described system using a Fourier transform infrared (FTIR) spectroscopy ‘lightpipe’ detector (i.e. when quantification was based on calibration using phthalate standards). When used to analyse natural organic matter (NOM) in water, it also had a superior signal-to-noise ratio to the previously described system. The use of a mass spectrometer to detect organic carbon (as CO 2) enables the possibility of further characterisation of NOM by measuring the stable carbon isotope ratios of the various molecular size fractions of organic carbon, as obtained by SEC.

Freshwaters: which NOM matters?

One of the difficulties encountered in the study of natural organic matter (NOM) in aquatic environments concerns terminology: a large number of different names and acronyms are used. In fact, this diversity merely reflects the variety of approaches applied to the study of NOM, leading to the definition and measurement of different operationally-defined fractions. As a result, the choice of the ‘best’ method to use and of the ‘best’ fraction to work on in a particular case is far from straightforward. This has as a consequence that often very simple methods for NOM characterisation are used in applied environmental studies and surveys. This study includes, first, a review of the most widely applied terminology, as described in over 500 articles, and, second, a first attempt at assessing how the panoply of methods available is really used in applied environmental studies.

Characterization of urban NOM in a municipal area with disused toxic waste sites

Natural organic matter (NOM) formed under urban conditions exhibits characteristic features reflecting the diversity of anthropogenically influenced soils. These NOM species indicate the state of the urban soil in respect of humification as well as contaminant loads and transport. Humic and fulvic acids isolated at two dump sites in the municipal area of Staßfurt (Germany) are characterized by a high oxygen functionality and a predominance of aliphatic structures. Permanent metal loads of soil humic acids mainly consist of Mg, Al, K and Fe. Soil fulvic acids are additionally loaded with Ca and Zn. The main feature of all humic and fulvic acids from the investigated area is an enrichment of chalcophile elements relative to the elemental distribution in the upper continental crust. Based on the permanent loads and other characteristics of the site-specific humic substances, an input of organic material from a waste dump into the aquifer could be demonstrated. Aquatic fulvic acids are charged along the ground water flow path, correlating with the elemental content of the dumped materials. A long-term observation of the seepage water path is recommended in order to assess the spreading behaviour of organically bound contaminant metals when humification proceeds.

Characterization of the Polarity of Natural Organic Matter under Ambient Conditions by the Polarity Rapid Assessment Method (PRAM)

The polarity rapid assessment method (PRAM) characterizes the polarity of aqueous natural organic matter (NOM) by quantifying the amount of material adsorbed onto different solid-phase extraction (SPE) sorbents. The analysis is performed under ambient conditions resulting in the elimination of pretreatment steps that may alterthe chemical characteristics of the NOM, allowing an accurate representation of its polarity as it exists in the environment. Additionally, analysis only requires 200 mL of sample and can be performed in 2 h. In this paper, the underlying theory of the method is presented, followed by its optimization, with emphasis on the development of conditions for the analysis of NOM in natural waters. A series of organic probe compounds showed that the most important physicochemical property describing the interaction between the NOM and the SPE sorbents was the hydrophobic surface area, allowing for the estimation of the hydrophobic character under ambient conditions. Evaluation of the effects of chemical concentration, pH, and ionic strength show that (1) concentration did not have an effect on PRAM characterization as long as the pH and ionic strength remained constant; (2) changes in pH and ionic strength resulted in considerable changes in PRAM characterization, as a result of the changes in configuration of the NOM; and (3) PRAM characterization of NOM can be completed in the concentration range of < 10 mg C/L, although this range could be expanded by evaluating the effect of concentration on a site-specific basis. Results indicate that measurement of both ultraviolet absorption and dissolved organic carbon show complementary results as they measure different aspects of NOM.

Natural organic matter fouling of low-pressure, hollow-fiber membranes: Effects of NOM source and hydrodynamic conditions

Effects of natural organic matter (NOM) source and hydrodynamic conditions on both hydraulically reversible and irreversible fouling of low-pressure, hollow-fiber (LPHF) membranes were systematically investigated using representative sources of natural waters and wastewater effluents. It was found that NOM source plays a primary role in determining the fouling of these membranes. Increase in permeate flux promoted membrane fouling, but to a lesser extent than NOM source. Permeate backwash flux appeared to restore permeability more effectively for the polyether sulfone (PES) membranes than to the polyvinylidene fluoride (PVDF) membranes used. NOM characterization revealed that organic colloids contributed predominantly to the hydraulically reversible fouling, and potentially to the irreversible fouling. Overall, this study demonstrated the importance of NOM source and the presence of organic colloids in the fouling of LPHF membranes, as well as the relevance of hydrodynamic operating conditions on the hydraulic reversibility of the fouling.

The application of electrospray ionization coupled to ultrahigh resolution mass spectrometry for the molecular characterization of natural organic matter

Mass spectrometry has recently played a key role in the understanding of natural organic matter (NOM) by providing molecular-level details about its composition. NOM, a complex assemblage of organic molecules present in natural waters and soils/sediments, has the ability to bind and transport anthropogenic materials. An improved understanding of its composition is crucial in order to understand how pollutants interact with NOM and how NOM cycles through global carbon cycles. In the past, low-resolution (>3000) mass analyzers have offered some insights into the structure of NOM, but emerging ultrahigh resolution (>200,000) techniques such as electrospray ionization (ESI) coupled to Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) have significantly advanced our knowledge of NOM chemistry. Here, a review of the recent literature on the advancements of NOM characterization and the applications of mass spectrometry to this central task is presented. Various methods for the analysis and display of the extremely complex mass spectra, such as the van Krevelen diagram and Kendrick mass defect analysis, are discussed. We also review tandem mass spectrometry techniques employed to gain structural information about NOM components. Finally, we show how ESI-FT-ICR-MS has been applied to examine specific issues that are important to the NOM scientific community, such as NOM reactivity, transport and fate, degradation, and existence of components, which are indicators of NOM origin. In general, ultrahigh resolution provided by FT-ICR-MS is essential for the complete separation of the thousands of peaks present in the complex NOM mixture and will clearly lead to additional future advancements in the areas of aquatic, soil, and analytical chemistry.

Reduction in vegetative growth of the water mold Saprolegnia parasitica (Coker) by humic substance of different qualities

Humic substances (HS) account for 50–80% of the dissolved organic matter in non-eutrophicated freshwater ecosystems. HS are not inert, but are taken up by and may interact with aquatic organisms. However, at present no information is available on the interaction of HS with fungi, for instance, the fish-pathogenous species Saprolegnia parasitica. To fill this gap, we tested effects of HS on S. parasitica growth in-vitro using 25–500 mg L −1 carbon of HS on GY-agar. We investigated 20 HS including natural organic matter (NOM) samples, two lignite derived HS, and one synthetic HS. The aim was (1) to find out, if there are inhibiting effects and (2) if potential effects can be explained by humic matter properties by structure activity relationships. The growth of S. parasitica was related to the growth on HS-free agar controls. Characterization of HS and NOMs included elemental analysis, high-pressure size exclusion chromatography (HPSEC), UV/VIS, FTIR-, and EPR-spectroscopy in order to obtain information on elemental and structural composition including various metals, molecular weights of the HS fraction, aromaticity, free organic radicals, and functional groups. NOMs with high moieties of high-molecular carbohydrates supported the growth of S. parasitica, all other HS and NOMs reduced it. However, no inhibition of the development of the sporangia and primary zoospores was found. Therefore, the impact of the HS on S. parasitica has to be classified as fungistatic, rather than fungicidal. Synthetic and lignite-derived HS were among the most efficient HS sources. Growth inhibition was correlated ( p < 0.05) with the molecular weights of the HS-fraction, sUVa, COOH groups, C and H. Our results suggest that especially HS with higher molecular weights and aromaticity which contain a high number of organic radicals are the most efficient in reducing fungal growth. Furthermore, highly functionalized HS seem to be important for the observed effect. The development of internal oxidative stress could be a mechanism explaining the observed growth inhibition of S. parasitica.

Analytical pyrolysis as a tool for the characterization of natural organic matter—A comparison of different approaches

A substantial fraction of natural organic matter (NOM) consists of complex mixtures of macromolecular compounds. As a result, high-molecular weight fragments liberated during the pyrolysis of NOM often carry the most significant structural information. Their diagnostic value, however, is commonly limited by the preferential transfer of lower-boiling pyrolysis products to the GC column, compared to larger fragments. Non-discriminating pyrolysis is a technique that minimizes transfer losses of larger fragments, which is the problem with most conventional pyrolyzers. It allows a range of sample sizes from ∼15 mg for the study of samples of low organic carbon content to estimated sub-microgram sizes for bacterial biomass. In this study, the performance of the non-discriminating pyrolysis system in the characterization of natural organic matter (NOM) was compared to the performance of a conventional Pt-filament pyrolyzer. In addition, a more limited comparison was carried out with a Curie-point system. A variety of organic materials were selected to serve as NOM models: chitin, peat, and organic matter isolated from tertiary sands. Non-discriminating pyrolysis-GC/MS allowed for the observation of larger molecular fragments, such as traces of cholesterol in the pyrolysis of chitin. Also, the distribution of the homologous series such as that observed for alkyl benzenes was shifted towards higher molecular weight fragments with the non-discriminating system. Overall, the macromolecular structures within NOM were more pronounced when using non-discriminating pyrolysis, as shown by the higher abundance in the pyrograms of higher molecular weight fragments of various polyaromatic and long-chain aliphatic compounds. Characterization of NOM using non-discriminating Py-GC/MS reduces the ambiguity caused by mass discrimination against higher mass fragments compared to other pyrolysis approaches. This provides a better fingerprint of the organic material present in different sample types, including soils and sediments.