Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Characterization of dissolved organic matter: An analytical challenge
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.ORCID iD: 0000-0002-4301-3923
2018 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Dissolved organic matter (DOM) is the prevalent form of organic carbon in most aquatic environments. It is an ultra-complex mixture that plays a crucial role in global carbon cycling. Despite its importance it is still poorly understood due to its extreme heterogeneity and intricacy. Major advances in chemical characterization of DOM were possible with the introduction of high-resolution mass spectrometry (HRMS). This technique, in combination with direct infusion (DI) as sample introduction, is the most powerful tool for the DOM analysis to date. A compelling alternative to DI is represented by upfront separation with liquid chromatography (LC); however, current techniques involve only offline LC-HRMS approaches, which exhibit important logistical drawbacks, making DOM analysis more challenging.

The aim of the presented studies was to develop new methods able to enhance the analysis of the dissolved organic matter and enable a wider range of researchers to participate in the advancement of this field.

In the first study, the application of the Orbitrap mass spectrometer for resolving complex DOM mixtures was investigated and the results were compared to the more established state-of-the-art technique, Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). The Orbitrap was capable of excellent reproducibility and detection of the majority of ionizable organic molecules in typical aquatic mixtures. The main disadvantage of the technique is that fewer molecular formulas can be resolved and detected because of lower resolution and sensitivity. This means that many sulfur peaks and all phosphorous containing peaks are not determined. Despite this drawback, our results suggest that the Orbitrap is an appropriate technique for the investigation of very subtle biogeochemical processing of bulk DOM. The lower costs (purchase and maintenance) and wider availability of Orbitrap mass spectrometers allow a greater number of laboratories to participate in the characterization of DOM.

In the second study, the first online method involving reverse phase chromatography and ultrahigh resolution mass spectrometry for the analysis of DOM was developed. This method overcomes the disadvantages of typical offline approaches. It enhances enormously the amount of information achievable in a single run, maintaining high resolution data, reducing analysis time and potential contamination. The introduction of in silico fractionation makes the method extremely flexible, allowing an easy, fast, and detailed comparison of DOM samples from a variety of sources.

Place, publisher, year, edition, pages
Uppsala: Department of Chemistry , 2018. , p. 46
National Category
Analytical Chemistry
Research subject
Chemistry with specialization in Analytical Chemistry
Identifiers
URN: urn:nbn:se:uu:diva-341690OAI: oai:DiVA.org:uu-341690DiVA, id: diva2:1182263
Presentation
2018-03-09, B7:101a, BMC, Husargatan 3, Uppsala, 10:15 (English)
Opponent
Supervisors
Available from: 2018-03-02 Created: 2018-02-12 Last updated: 2018-03-02Bibliographically approved
List of papers
1. Evaluation of the Orbitrap Mass Spectrometer for the Molecular Fingerprinting Analysis of Natural Dissolved Organic Matter
Open this publication in new window or tab >>Evaluation of the Orbitrap Mass Spectrometer for the Molecular Fingerprinting Analysis of Natural Dissolved Organic Matter
Show others...
2016 (English)In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 88, no 15, p. 7698-7704Article in journal (Refereed) Published
Abstract [en]

We investigated the application of the LTQ-Orbitrap mass spectrometer (LTQ-Velos Pro, Thermo Fisher) for resolving complex mixtures of natural aquatic dissolved organic matter (DOM) and compared this technique to the more established state-of-the-art technique, Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS, Bruker Daltonics), in terms of the distribution of molecular masses detected and the reproducibility of the results collected. The Orbitrap was capable of excellent reproducibility: Bray-Curtis dissimilarity between duplicate measurements was 2.85 +/- 0.42% (mean +/- standard deviation). The Orbitrap was also capable of the detection of most major ionizable organic molecules in typical aquatic mixtures, with the exception of most sulfur and phosphorus containing masses. This result signifies that the Orbitrap is an appropriate technique for the investigation of very subtle biogeochemical processing of bulk DOM. The lower costs (purchase and maintenance) and wider availability of Orbitrap mass spectrometers in university departments means that the tools necessary for research into DOM processing at the molecular level should be accessible to a much wider group of scientists than before. The main disadvantage of the technique is that substantially fewer molecular formulas can be resolved from a complex mixture (roughly one third as many), meaning some loss of information. In balance, most biogeochemical studies that aim at molecularly fingerprinting the source of natural DOM could be satisfactorily carried out with Orbitrap mass spectrometry. For more targeted metabolomic studies where individual compounds are traced through natural systems, FTICR-MS remains advantageous.

National Category
Analytical Chemistry
Identifiers
urn:nbn:se:uu:diva-303281 (URN)10.1021/acs.analchem.6b01624 (DOI)000380967800039 ()27400998 (PubMedID)
Funder
Knut and Alice Wallenberg Foundation, KAW 2013.0091
Available from: 2016-09-16 Created: 2016-09-15 Last updated: 2018-02-12Bibliographically approved
2. Online HPLC-ESI-HRMS Method for the Analysis and Comparison of Different Dissolved Organic Matter Samples
Open this publication in new window or tab >>Online HPLC-ESI-HRMS Method for the Analysis and Comparison of Different Dissolved Organic Matter Samples
Show others...
2018 (English)In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 52, no 4, p. 2091-2099Article in journal (Refereed) Published
Abstract [en]

Natural dissolved organic matter (DOM) is an ultracomplex mixture that is essential to global carbon cycling but is poorly understood because of its complexity. The most powerful tool for the DOM characterization is high-resolution mass spectrometry (HRMS) generally combined to direct infusion (DI) as sample introduction. Liquid chromatography (LC) represents a compelling alternative to DI; however, state-of-the-art techniques involve only offline LC-HRMS approaches, which have important logistical drawbacks that make DOM analysis more challenging. This study introduces a new method based on online coupling of liquid chromatography to high resolution mass spectrometry, able to overcome the disadvantages of usual approaches. It is characterized by high reproducibility (% Bray–Curtis dissimilarity among replicates ≈ 2.5%), and it reduces transient complexity and contaminant interferences, thus increasing the signal-to-noise ratio (S/N), leading to the identification of an overall larger number of formulas in the mixture. Moreover, the application of an in silico fractionation prior to the statistical analysis allows an easy, flexible, fast, and detailed comparison of DOM samples from a variety of sources with a single chromatographic run.

National Category
Analytical Chemistry
Research subject
Chemistry with specialization in Analytical Chemistry
Identifiers
urn:nbn:se:uu:diva-341015 (URN)10.1021/acs.est.7b04508 (DOI)000426143300045 ()
Funder
Knut and Alice Wallenberg Foundation, 2013.0091Swedish Research Council, SRC 2015-4870Swedish Research Council, SRC 2014-04264
Available from: 2018-02-06 Created: 2018-02-06 Last updated: 2018-04-19Bibliographically approved

Open Access in DiVA

fulltext(1078 kB)47 downloads
File information
File name FULLTEXT01.pdfFile size 1078 kBChecksum SHA-512
aeaed8cd9d5da5ae2f1807e064f1f8146c073416276861065631e5586d37a524c49b65972ff214f6f916b79813a6a7584946e087b3faa5853903e853e87a1590
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Patriarca, Claudia
By organisation
Analytical Chemistry
Analytical Chemistry

Search outside of DiVA

GoogleGoogle Scholar
Total: 47 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

urn-nbn

Altmetric score

urn-nbn
Total: 147 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf