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SALDI-MS Signal Enhancement Using Oxidized Graphitized Carbon Black Nanoparticles
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för analytisk kemi.
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för analytisk kemi.
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för analytisk kemi.
2009 (engelsk)Inngår i: Journal of the American Society for Mass Spectrometry, ISSN 1044-0305, E-ISSN 1879-1123, Vol. 20, nr 6, s. 1207-1213Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The signal intensity of low-molecular-weight compounds analyzed using surface-assisted laserdesorption/ionization time-of-flight mass spectrometry (SALDI-TOF-MS) was significantlyenhanced when oxidized graphitized carbon black (GCB) particles were used as the desorption/ionization surface. The surface of oxidized GCB contains more carboxylic acid groupsthan non-oxidized GCB. Carboxylic acid groups enhance the efficiency of the ionizationprocess and the desorption of more hydrophobic compounds. A common pharmaceuticalcompound, propranolol, was successfully extracted from Baltic Sea blue mussels and quantifiedusing oxidized GCB as the SALDI surface, whereas deuterated propranolol was used asthe internal standard. The calibration curve showed a wide linear dynamic range of response(0.1–20 g/mL) and good reproducibility (RSD 10%). It was not possible to detectpropranolol in Baltic Sea blue mussels when non-oxidized GCB was used as the SALDI surface.

sted, utgiver, år, opplag, sider
2009. Vol. 20, nr 6, s. 1207-1213
Identifikatorer
URN: urn:nbn:se:su:diva-38262DOI: 10.1016/j.jasms.2009.02.017ISI: 000266466600036OAI: oai:DiVA.org:su-38262DiVA, id: diva2:308472
Tilgjengelig fra: 2010-04-06 Laget: 2010-04-06 Sist oppdatert: 2017-12-12bibliografisk kontrollert
Inngår i avhandling
1. Novel Solid Phase Extraction and Mass Spectrometry Approaches to Multicomponent Analyses in Complex Matrices
Åpne denne publikasjonen i ny fane eller vindu >>Novel Solid Phase Extraction and Mass Spectrometry Approaches to Multicomponent Analyses in Complex Matrices
2010 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

Analysis of compounds present in complex matrices is always a challenge, which can be partly overcome by applying various sample preparation techniques prior to detection. Ideally, the extraction techniques should be as selective as possible, to minimize the concentration of interfering substances. In addition, results can be improved by efficient chromatographic separation of the sample components. The elimination of interfering substances is especially important when utilizing mass spectrometry (MS) as a detection technique since they influence the ionization yields. It is also important to optimize ionization methods in order to minimize detection limits.

In the work this thesis is based upon, selective solid phase extraction (SPE) materials, a restricted access material (RAM) and graphitized carbon black (GCB) were employed for clean up and/or pre-concentration of analytes in plasma, urine and agricultural drainage water prior to liquid chromatography/mass spectrometry (LC/MS). Two SPE formats, in which GCB was incorporated in µ-traps and disks, were developed for cleaning up small and large volume samples, respectively. In addition, techniques based on use of sub-2 µm C18 particles at elevated temperatures and a linear ion trap (LIT) mass spectrometer were developed to improve the efficiency of LC separation and sensitivity of detection of 6-formylindolo[3,2-b]carbazole (FICZ) metabolites in human urine.

It was also found that GCB can serve not only as a SPE sorbent, but also as a valuable surface for surface-assisted laser desorption ionization (SALDI) of small molecules. The dual functionality of GCB was utilized in a combined screening-identification/quantification procedure for fast elimination of negative samples. This may be particularly useful when processing large numbers of samples. SALDI analyses of small molecules was further investigated and improved by employing two kinds of new surfaces: oxidized GCB nanoparticles and silicon nitride.

sted, utgiver, år, opplag, sider
Stockholm: Department of Analytical Chemistry, Stockholm University, 2010. s. 62
Emneord
Sample preparation, SPE, RAM, GCB µ-trap, GCB disk, High temperature LC, LC/MS, ESI, APCI, Matrix effects, LIT-MS, SALDI, Sample screening, Oxidized GCB, Silicon nitride
HSV kategori
Forskningsprogram
analytisk kemi
Identifikatorer
urn:nbn:se:su:diva-38625 (URN)978-91-7447-050-5 (ISBN)
Disputas
2010-06-02, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 16 B, Stockholm, 10:00 (engelsk)
Opponent
Veileder
Tilgjengelig fra: 2010-05-11 Laget: 2010-04-22 Sist oppdatert: 2010-05-04bibliografisk kontrollert
2. Novel clean-up, concentration and laser desorption/ionization strategies for mass spectrometry
Åpne denne publikasjonen i ny fane eller vindu >>Novel clean-up, concentration and laser desorption/ionization strategies for mass spectrometry
2010 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

Despite valuable advantages of mass spectrometry (MS) techniques they still have drawbacks that need to be overcome, notably their sensitivity to various kinds of interfering substances and associated difficulties involved in detecting signals from analytes present in trace quantities. Thus, high quality analytical data could be acquired by improving sample pre-treatment techniques and/or ionization methods to increase ionization yields and/or avoid the generation of unwanted ions.

In the studies this thesis is based upon, a microfluidic electrocapture system capable of trapping charged proteins/polypeptides while non-charged species such as non-ionic detergents are swept out, was used to decrease the concentration of detergent in samples containing soluble and membrane associated proteins/polypeptide. Subsequent mass spectrometric analysis yielded well-resolved mass spectra of the target analytes.

In addition, it was found that solid phase extraction (SPE) sorbents such as graphitized carbon black (GCB), can efficiently assist the laser desorption ionization of small molecules without generating any interfering ions which inspired the fabrication of μ-traps and discs. Other matrix-free approaches demonstrated the utility of silicon nitride and oxidized GCB nanoparticles as versatile media for surface-assisted laser desorption ionization (SALDI) of small molecules.

In this thesis it is discussed that small molecule analytes such as Polyphenols present in red wine and quaternary protoberberine alkaloids with highly conjugated systems and acidic/permanently charged functional groups can be readily analyzed without any matrix or assisting-surface.

In summary, the microfluidic electrocapture, new laser desorption ionization methods and surfaces, as well as integrated SALDI and SPE platforms, introduced in this work extend the MS strategies allowing coverage of a wider range of samples.

sted, utgiver, år, opplag, sider
Stockholm: Department of Analytical Chemistry, Stockholm University, 2010. s. 77
Emneord
Mass spectrometry, ESI-MS, SALDI-MS, Electrocapture, Sample treatment
HSV kategori
Forskningsprogram
analytisk kemi
Identifikatorer
urn:nbn:se:su:diva-32236 (URN)978-91-7155-981-4 (ISBN)
Disputas
2010-01-22, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 16 B, Stockholm, 10:00 (engelsk)
Opponent
Veileder
Merknad
At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: In PressTilgjengelig fra: 2009-12-17 Laget: 2009-12-07 Sist oppdatert: 2011-08-31bibliografisk kontrollert

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