uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • 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
Comparison between different sheathless electrospray emitter configurations regarding the performance of nanoscale liquid chromatography time-of-flight mass spectrometry analysis
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
Show others and affiliations
2004 (English)In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1033, no 2, 257-266 p.Article in journal (Refereed) Published
Abstract [en]

Four different sheathless electrospray ionization (ESI) configurations were investigated for a nano liquid chromatography (LC) system. The studied configurations were: a column with an integrated emitter, with the ESI potential applied before or after the column, and a column with separate emitter, with the ESI voltage applied at a union before the emitter or at the emitter tip. The results indicates that the efficiency of the LC system is rather independent of the configuration when using 95 μm i.d. columns, acetic mobile phase and standard peptides as a sample. Introduction of post column dead volume seems not to be a critical issue at least with flow rates down to 600 nl/min.

Place, publisher, year, edition, pages
2004. Vol. 1033, no 2, 257-266 p.
Keyword [en]
Electrospray ionization, Band broadening, Principal component analysis, Instrumentation, Peptides
National Category
Chemical Sciences
Identifiers
URN: urn:nbn:se:uu:diva-91889DOI: 10.1016/j.chroma.2004.01.063OAI: oai:DiVA.org:uu-91889DiVA: diva2:164758
Available from: 2004-05-25 Created: 2004-05-25 Last updated: 2012-02-08Bibliographically approved
In thesis
1. Development of Sheathless Electrospray Mass Spectrometry and Investigations of Associated Electrochemical Processes – A Fairy Tale
Open this publication in new window or tab >>Development of Sheathless Electrospray Mass Spectrometry and Investigations of Associated Electrochemical Processes – A Fairy Tale
2004 (English)Doctoral thesis, comprehensive summary (Other academic)
Alternative title[sv]
Utveckling av lågflödeselektrospray-masspektrometri samt undersökningar av associerade elektrokemiska processer – en fésaga
Abstract [en]

In microscale separations, such as capillary electrophoresis and -liquid chromatography, the liquid flow rates are in the order of nanoliters per second. If such flow rates are to be interfaced with a mass spectrometer (MS) using electrospray (ES) ionization, without loss of separation efficiency, each fraction of the analyte zone must remain undisturbed by the high voltage contact necessary for ES. One design that accomplishes this is the pure sheathless approach, where a thin, vapor deposited metal film covers the outside of the electrospray emitter tip.

This thesis describes the development of such sheathless emitters. The lifetimes of polymer embedded gold (“fairy dust”) or graphite (“black dust”) emitters were shown to by far exceed those of previously used conductive films. In addition, the production of emitters with these coatings was substantially simplified. The increase in durability was found to be due to enhanced resistance towards the electrochemical processes associated with ES. In analogy, the reasons for the limited durability of previously used methods were correlated with their tendency to oxidize, or be mechanically removed, during electrochemical reactions.

Electrochemical processes associated with the electrospray potential were also found to seriously disturb analyses in which porous graphitic carbon was used as the separation medium. A proper choice of grounding point locations eliminated these disturbances.

At last, the differences regarding analytical performance of several sheathless interface configurations, used in capillary liquid chromatography, were examined. The best performance was obtained when a pure sheathless emitter with a conductive layer of polyimide and graphite was coupled to the LC column through a Teflon sleeve.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2004. 41 p.
Series
Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1104-232X ; 989
Keyword
Analytical chemistry, electrospray, sheathless, mass spectrometry, capillary electrophoresis, electrochemistry, chromatography, interface, fairy dust, gold, Analytisk kemi
National Category
Analytical Chemistry
Identifiers
urn:nbn:se:uu:diva-4293 (URN)91-554-5989-7 (ISBN)
Public defence
2004-09-10, Room B 41, BMC - Uppsala Biomedical Center, Husargatan 3, Uppsala, 10:15
Opponent
Supervisors
Available from: 2004-05-25 Created: 2004-05-25Bibliographically approved
2. Development of Techniques and Methods for the Quantitative Analysis of Endogenous Substances by Microcolumn Liquid Chromatography Coupled to Mass Spectrometry
Open this publication in new window or tab >>Development of Techniques and Methods for the Quantitative Analysis of Endogenous Substances by Microcolumn Liquid Chromatography Coupled to Mass Spectrometry
2004 (English)Doctoral thesis, comprehensive summary (Other academic)
Alternative title[sv]
Utveckling av tekniker och metoder för kvantitativ analys av endogena substanser med mikrokolonn vätskekromatografi sammankopplad med masspektrometri
Abstract [en]

Liquid chromatography-mass spectrometry (LC-MS) is a powerful technique for the analysis of endogenous compounds. The introduction of electrospray ionization (ESI) as an interface between LC and MS has contributed strongly to a trend towards miniaturization of LC, due to the possibility to perform ESI at low flow rates. In this thesis, several aspects regarding the design of miniaturized LC systems and electrospray emitters were investigated. In addition miniaturized LC-ESI-MS have been used for the qualitative and quantitative analysis of endogenous polar compounds, peptides and protein digests.

The performance of miniaturized LC-MS was compared using different electrospray emitter configurations. The results indicated that the efficiency of the LC system is rather independent of the configuration of the emitter.

The lifetime of gold-coated fused silica electrospray emitters based on vapor deposited adhesion layers of titanium were investigated. The long lifetime of the emitter facilitates the use in LC-MS experiments, exemplified LC-MS by analysis of neuropeptides.

The ESI voltage is shown to interfere with liquid chromatographic separations performed in packed porous graphitic carbon capillary column. This interference is ascribed to the presence of an electric field over the conductive column in absence of a ground point between the column and the ESI emitter.

The solid supported enhanced microdialysis for analysis of neuropeptides were compared with conventional microdialysis. The difference between the two methodologies were evaluated by LC-MS analysis of the microdialysates. The solid supported method gave in general higher relative recoveries.

Finally, a method of standard addition was developed to determine total level of tryptophan and two of its metabolites in human plasma by capillary LC-ESI tandem mass spectrometry. The method was applied in a clinical study of multiple scleroses patients treated with cytokines (IFN Beta 1a, 1b). The results show that the intervention effects the tryptophan metabolism.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2004. 48 p.
Series
Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1104-232X ; 936
Keyword
Analytical chemistry, Analytisk kemi
National Category
Analytical Chemistry
Identifiers
urn:nbn:se:uu:diva-3990 (URN)91-554-5869-6 (ISBN)
Public defence
2004-02-20, B 41, BMC, Husargatan 3 75 237, Uppsala, 10:15
Opponent
Supervisors
Available from: 2004-01-30 Created: 2004-01-30 Last updated: 2013-06-14Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Authority records BETA

Wetterhall, MagnusBergquist, Jonas

Search in DiVA

By author/editor
Wetterhall, MagnusBergquist, Jonas
By organisation
Analytical Chemistry
In the same journal
Journal of Chromatography A
Chemical Sciences

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 922 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • 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