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
Capillary electrophoresis coupled to mass spectrometry from a polymer modified poly(dimethylsiloxane) microchip with an integrated graphite electrospray tip
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
2005 (English)In: The Analyst, ISSN 0003-2654, E-ISSN 1364-5528, Vol. 130, no 2, 193-199 p.Article in journal (Refereed) Published
Abstract [en]

Hybrid capillary-poly(dimethysiloxane) (PDMS) microchips with integrated electrospray ionization (ESI) tips were directly fabricated by casting PDMS in a mould. The shapes of the emitter tips were drilled into the mould, which produced highly reproducible three-dimensional tips. Due to the fabrication method of the microfluidic devices, no sealing was necessary and it was possible to produce a perfect channel modified by PolyE-323, an aliphatic polyamine coating agent. A variety of different coating procedures were also evaluated for the outside of the emitter tip. Dusting graphite on a thin unpolymerised PDMS layer followed by polymerisation was proven to be the most suitable procedure. The emitter tips showed excellent electrochemical properties and durabilities. The coating of the emitter was eventually passivated, but not lost, and could be regenerated by electrochemical means. The excellent electrochemical stability was further confirmed in long term electrospray experiments, in which the emitter sprayed continuously for more than 180 h. The PolyE-323 was found suitable for systems that integrate rigid fused silica and soft PDMS technology, since it simply could be applied successfully to both materials. The spray stability was confirmed from the recording of a total ion chromatogram in which the electrospray current exhibited a relative standard deviation of 3.9% for a 30 min run. CE-ESI-MS separations of peptides were carried out within 2 min using the hybrid PDMS chip resulting in similar efficiencies as for fused silica capillaries of the same length and thus with no measurable band broadening effects, originating from the PDMS emitter.

Place, publisher, year, edition, pages
2005. Vol. 130, no 2, 193-199 p.
National Category
Analytical Chemistry Inorganic Chemistry
Identifiers
URN: urn:nbn:se:uu:diva-93084DOI: 10.1039/b414592ePubMedID: 15665973OAI: oai:DiVA.org:uu-93084DiVA: diva2:166454
Available from: 2005-05-03 Created: 2005-05-03 Last updated: 2017-12-14Bibliographically approved
In thesis
1. Development and Investigations of Novel Sample Preparation Techniques: Electrochemical Extraction and Evaluation of Miniaturized Analytical Devices Coupled to Mass Spectrometry
Open this publication in new window or tab >>Development and Investigations of Novel Sample Preparation Techniques: Electrochemical Extraction and Evaluation of Miniaturized Analytical Devices Coupled to Mass Spectrometry
2005 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Different sample preparation steps prior to a detection method are often essential in analytical chemistry. In this thesis, both static extractions and on-line coupled solid-phase extractions have been studied in combination with different detection techniques. Aspects of performing sample preparations in miniaturized analytical devices and the development of poly(dimethylsiloxane) (PDMS) microchips are discussed. Polypyrrole was also evaluated as an electrochemically controllable stationary phase for solid-phase microextraction (SPME) and solid-phase extraction (SPE).

The first part of this thesis describes the extraction of an organic compound from a very complex solid matrix utilizing the pressurized-fluid extraction (PFE) technique. The presented results show that PFE is easily optimized and enables rapid extractions and extracts relatively free from interferences.

An integrated three-electrode device, which enabled electrochemical (EC) SPME under potential control, was developed. With this device, both anions and cations could be extracted employing two types of polypyrrole films. Planar micro band electrodes positioned at the end of a capillary were also used to electrochemically extract and detect anions in a miniaturized flow system. Different analyte concentrations and preconcentration times were examined, and good linear correlations were found between the extraction time and the detection response. The on-line coupling of a thin layer EC cell, with a polypyrrole coated working electrode, to different mass spectrometric (MS) techniques is also described and evaluated. The results show that EC-SPE, employing polypyrrole as stationary phase, can be used as a preconcentration step prior to detection.

In addition, this thesis describes the development and on-line coupling of a microelectrode array equipped PDMS microchip with an integrated graphite electrospray emitter to electrospray ionization (ESI) MS. The system enabled short transfer times and an EC conversion efficiency of 30% at a flow rate of 0.5 μL/min. The on-line EC/ESI-MS experiments were significantly simplified using a wireless Bluetooth battery-powered EC instrument.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2005. 51 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 54
Keyword
Analytical chemistry, Electrochemical extraction, Solid-phase microextraction, Solid-phase extraction, Microchip, Mass spectrometry, Polypyrrole, Pressurized-fluid extraction, Preconcentration, Electrospray ionization, Analytisk kemi
National Category
Analytical Chemistry
Identifiers
urn:nbn:se:uu:diva-5807 (URN)91-554-6256-1 (ISBN)
Public defence
2005-06-02, Room B41, BMC, Uppsala Biomedical Center, Uppsala, 13:15
Opponent
Supervisors
Available from: 2005-05-03 Created: 2005-05-03Bibliographically approved
2. Microscale Tools for Sample Preparation, Separation and Detection of Neuropeptides
Open this publication in new window or tab >>Microscale Tools for Sample Preparation, Separation and Detection of Neuropeptides
2005 (English)Doctoral thesis, comprehensive summary (Other academic)
Alternative title[sv]
Mikroskaliga verktyg för provpreparering, separation och detektion av neuropeptider
Abstract [en]

The analysis of low abundant biological molecules is often challenging due to their chemical properties, low concentration and limited sample volumes. Neuropeptides are one group of molecules that fits these criteria. Neuropeptides also play an important role in biological functions, which makes them extra interesting to analyze. A classic chemical analysis involves sampling, sample preparation, separation and detection. In this thesis, an enhanced solid supported microdialysis method was developed and used as a combined sampling- and preparation technique. In general, significantly increased extraction efficiency was obtained for all studied peptides. To be able to control the small sample volumes and to minimize the loss of neuropeptides because of unwanted adsorption onto surfaces, the subsequent analysis steps were miniaturized to a micro total analysis system (µ-TAS), which allowed sample pre-treatment, injection, separation, manipulation and detection.

In order to incorporate these analysis functions to a microchip, a novel microfabrication protocol was developed. This method facilitated three-dimensional structures to be fabricated without the need of clean room facilities.

The sample pre-treatment step was carried out by solid phase extraction from beads packed in the microchip. Femtomole levels of neuropeptides were detected from samples possessing the same properties as microdialysates. The developed injection system made it possible to conduct injections from a liquid chromatographic separation into a capillary electrophoresis channel, which facilitated for advanced multidimensional separations. An electrochemical sample manipulation system was also developed. In the last part, different electrospray emitter tip designs made directly from the edge of the microchip substrate were developed and evaluated. The emitters were proven to be comparable with conventional, capillary based emitters in stability, durability and dynamic flow range. Although additional developments remain, the analysis steps described in this thesis open a door to an integrated, on-line µ-TAS for neuropeptides analysis in complex biological samples.

Place, publisher, year, edition, pages
Uppsala: Kemiska institutionen, 2005. 62 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 64
Keyword
Analytical chemistry, Neuropeptides, Microchip, Enhanced microdialysis, Poly(dimethylsiloxane) (PDMS), Electrospray ionization (ESI), Multidimensional separation, Electrochemical manipulation, Mass spectrometry (MS), Capillary electrophoresis (CE), Microdevice, Microfabrication, Micro total analysis system (μ-TAS), Analytisk kemi
National Category
Analytical Chemistry
Identifiers
urn:nbn:se:uu:diva-5838 (URN)91-554-6279-0 (ISBN)
Public defence
2005-06-03, Room B42, BMC, Uppsala, 10:15
Opponent
Supervisors
Available from: 2005-05-10 Created: 2005-05-10 Last updated: 2011-12-08Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textPubMed

Authority records BETA

Wetterhall, MagnusBergström, Sara K.Andrén, PerNyholm, LeifBergquist, Jonas

Search in DiVA

By author/editor
Wetterhall, MagnusBergström, Sara K.Andrén, PerNyholm, LeifBergquist, Jonas
By organisation
Analytical ChemistryDepartment of Pharmaceutical BiosciencesMaterials Chemistry
In the same journal
The Analyst
Analytical ChemistryInorganic Chemistry

Search outside of DiVA

GoogleGoogle Scholar

doi
pubmed
urn-nbn

Altmetric score

doi
pubmed
urn-nbn
Total: 1000 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