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

Direct link
BETA
Shevchenko, Denys
Publications (5 of 5) Show all publications
Bergman, N., Shevchenko, D. & Bergquist, J. (2014). Approaches for the analysis of low molecular weight compounds with laser desorption/ionization techniques and mass spectrometry. Analytical and Bioanalytical Chemistry, 406(1), 49-61
Open this publication in new window or tab >>Approaches for the analysis of low molecular weight compounds with laser desorption/ionization techniques and mass spectrometry
2014 (English)In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 406, no 1, p. 49-61Article, review/survey (Refereed) Published
Abstract [en]

This review summarizes various approaches for the analysis of low molecular weight (LMW) compounds by different laser desorption/ionization mass spectrometry techniques (LDI-MS). It is common to use an agent to assist the ionization, and small molecules are normally difficult to analyze by, e.g., matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS) using the common matrices available today, because the latter are generally small organic compounds themselves. This often results in severe suppression of analyte peaks, or interference of the matrix and analyte signals in the low mass region. However, intrinsic properties of several LDI techniques such as high sensitivity, low sample consumption, high tolerance towards salts and solid particles, and rapid analysis have stimulated scientists to develop methods to circumvent matrix-related issues in the analysis of LMW molecules. Recent developments within this field as well as historical considerations and future prospects are presented in this review.

Keywords
MALDI, SALDI, SELDI, Mass spectrometry, Derivatizations, Small molecules
National Category
Natural Sciences
Identifiers
urn:nbn:se:uu:diva-216925 (URN)10.1007/s00216-013-7471-3 (DOI)000329092900011 ()
Available from: 2014-01-27 Created: 2014-01-27 Last updated: 2017-12-06Bibliographically approved
Bergman, N., Thapper, A., Styring, S., Bergquist, J. & Shevchenko, D. (2014). Quantitative determination of the Ru(bpy)(3)(2+) cation in photochemical reactions by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Analytical Methods, 6(21), 8513-8518
Open this publication in new window or tab >>Quantitative determination of the Ru(bpy)(3)(2+) cation in photochemical reactions by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry
Show others...
2014 (English)In: Analytical Methods, ISSN 1759-9660, E-ISSN 1759-9679, Vol. 6, no 21, p. 8513-8518Article in journal (Refereed) Published
Abstract [en]

The coordination compound of Ru(II) with three 2,2'-bipyridine ligands possesses a potent photosensitization capacity for electron- and energy-transfer processes. In combination with salts of peroxydisulfate acid as sacrificial electron acceptors, Ru(bpy)(3)(2+) is widely used for photocatalytic oxidative transformations in organic synthesis and water splitting. The drawback of this system is that bipyridine degrades under the resulting strongly oxidative conditions, the concentration of Ru(bpy)(3)(2+) diminishes, and the photocatalytic reaction eventually stops. A commonly employed assay for the determination of Ru(bpy)(3)(2+), UV-Vis spectroscopy, has low selectivity and does not distinguish between the intact complex and its decayed forms. Here, we report a matrix assisted laser desorption/ionisation mass spectrometric method for the quantitative analysis of Ru(bpy)(3)(2+) in photochemical reaction mixtures. The developed method was successfully used for the determination of intact Ru(bpy)(3)(2+) during the course of the water photooxidation reaction. The significant difference between the results of MALDI MS and UV-Vis analyses was observed.

National Category
Chemical Sciences
Identifiers
urn:nbn:se:uu:diva-237893 (URN)10.1039/c4ay01379d (DOI)000343737100010 ()
Available from: 2014-12-11 Created: 2014-12-08 Last updated: 2017-12-05Bibliographically approved
Shevchenko, D., Anderlund, M. F., Styring, S., Dau, H., Zaharieva, I. & Thapper, A. (2014). Water oxidation by manganese oxides formed from tetranuclear precursor complexes: the influence of phosphate on structure and activity. Physical Chemistry, Chemical Physics - PCCP, 16(24), 11965-11975
Open this publication in new window or tab >>Water oxidation by manganese oxides formed from tetranuclear precursor complexes: the influence of phosphate on structure and activity
Show others...
2014 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 16, no 24, p. 11965-11975Article in journal (Refereed) Published
Abstract [en]

Two types of manganese oxides have been prepared by hydrolysis of tetranuclear Mn(III) complexes in the presence or absence of phosphate ions. The oxides have been characterized structurally using X-ray absorption spectroscopy and functionally by O-2 evolution measurements. The structures of the oxides prepared in the absence of phosphate are dominated by di-mu-oxo bridged manganese ions that form layers with limited long-range order, consisting of edge-sharing MnO6 octahedra. The average manganese oxidation state is +3.5. The structure of these oxides is closely related to other manganese oxides reported as water oxidation catalysts. They show high oxygen evolution activity in a light-driven system containing [Ru(bpy)(3)](2+) and S2O82- at pH 7. In contrast, the oxides formed by hydrolysis in the presence of phosphate ions contain almost no di-mu-oxo bridged manganese ions. Instead the phosphate groups are acting as bridges between the manganese ions. The average oxidation state of manganese ions is +3. This type of oxide has much lower water oxidation activity in the light-driven system. Correlations between different structural motifs and the function as a water oxidation catalyst are discussed and the lower activity in the phosphate containing oxide is linked to the absence of protonable di-mu-oxo bridges.

National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-228523 (URN)10.1039/c3cp55125c (DOI)000337122000016 ()
Available from: 2014-07-16 Created: 2014-07-16 Last updated: 2017-12-05Bibliographically approved
Shevchenko, D., Huang, P., Bon, V. V., Anderlund, M. F., Kokozay, V. N., Styring, S. & Thapper, A. (2013). Synthesis, crystal structure, mass spectrometry, electrochemistry and magnetism of a Mn-III-substituted trilacunary Keggin tungstosilicate. Dalton Transactions, 42(14), 5130-5139
Open this publication in new window or tab >>Synthesis, crystal structure, mass spectrometry, electrochemistry and magnetism of a Mn-III-substituted trilacunary Keggin tungstosilicate
Show others...
2013 (English)In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 42, no 14, p. 5130-5139Article in journal (Refereed) Published
Abstract [en]

A rare example of a "monomeric" triple transition-metal substituted Keggin anion has been synthesized and characterized by various methods including X-ray crystallography, ESI and MALDI mass spectrometry, electrochemistry, EPR, and SQUID.

National Category
Natural Sciences
Identifiers
urn:nbn:se:uu:diva-198641 (URN)10.1039/c3dt12500a (DOI)000316295500045 ()
Available from: 2013-04-22 Created: 2013-04-22 Last updated: 2017-12-06Bibliographically approved
Shevchenko, D., Anderlund, M. F., Thapper, A. & Styring, S. (2011). Photochemical water oxidation with visible light using a cobalt containing catalyst. Energy and Environmental Science, 4(4), 1284-1287
Open this publication in new window or tab >>Photochemical water oxidation with visible light using a cobalt containing catalyst
2011 (English)In: Energy and Environmental Science, ISSN 1754-5692, Vol. 4, no 4, p. 1284-1287Article in journal (Refereed) Published
Abstract [en]

Artificial photosynthesis aims at using solar light energy to oxidatively split water to oxygen, protons and electrons and store the energy in a chemical fuel. Here we present a cobalt phosphonate material that can split water catalytically, driven by visible light in aqueous solutions of pH 7.

Place, publisher, year, edition, pages
RSC Publishing, 2011
National Category
Chemical Sciences Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-152647 (URN)10.1039/c0ee00585a (DOI)000289001400018 ()
Available from: 2011-04-29 Created: 2011-04-29 Last updated: 2013-03-08Bibliographically approved
Organisations

Search in DiVA

Show all publications