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Budapest, Hungary

Karady M.,Palacky University | Novak O.,Palacky University | Horna A.,RadAnal Ltd. | Horna A.,Tomas Bata University in Zlin | And 2 more authors.
Electroanalysis | Year: 2011

On-line LC-EC/ESI-MS has been established as a fast and simple method to mimic some types of oxidation reaction of various drugs and to study the formation and structure of the resulting products. This technique has been applied to a 2,6,9-trisubstituted purine, R-roscovitine, which is known to be an inhibitor of some cyclin-dependent kinases (CDKs) and a potential anticancer drug. Oxidation of R-roscovitine in an electrochemical cell (EC), operated under various conditions, resulted in appearance of 6 major products. These were further analyzed by high-resolution mass spectrometry, their structures were elucidated by accurate mass measurement and compared to previously identified R-roscovitine in vitro/in vivo metabolites. Although none of the observed products was structurally identical to those identified previously in vitro/in vivo, all of them, except for the methoxylated products, resembled similarity due to appearing through the same reaction type. R-roscovitine in the EC cell underwent N-dealkylation of the isopropyl moiety, hydroxylation of the aromatic side-chain, dihydroxylation, methoxylation and dimer formation. The hydroxylation product was identified as Olomoucine II, a R-roscovitine derivative, which displays 10-times higher CDK-inhibiting activity than R-roscovitine and the occurrence of which, as R-roscovitine product, has not yet been observed in vitro/in vivo. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Ligor M.,Nicolaus Copernicus University | Studzinska S.,Nicolaus Copernicus University | Horna A.,RadAnal Ltd. | Buszewski B.,Nicolaus Copernicus University
Critical Reviews in Analytical Chemistry | Year: 2013

An alternative to other universal detection methods like refractive index (RI), low wavelength or ultraviolet (UV), and evaporative light scattering detection (ELSD), chemiluminescent nitrogen detection is a relatively new method based upon aerosol charging and involves Corona-charged aerosol detection (Corona-CAD). Some reports show that the sensitivity of this method is lower than that of fluorescence detection. Others confirm approximately five times higher sensitivity than conventional UV absorbance detection for selected analytes. This is the reason that Corona-CAD can be widely used for the determination of nonvolatile or semivolatile compounds, including: lipids, oligosaccharides, carbohydrates, proteins, steroids, surfactants, polymers, peptides, and others. The response of Corona-CAD is independent of chemical properties of the analyte. This article reviews applications of Corona-CAD and principles of the aerosol charging method as well as advantages and disadvantages of the method. The modern solution using an ultra detector, which brings charged aerosol detection to UHPLC, is also discussed. © 2013 Copyright Taylor and Francis Group, LLC. Source


Vajda N.,RadAnal Ltd. | Kim C.-K.,International Atomic Energy Agency
Applied Radiation and Isotopes | Year: 2010

A great number of analytical methods have been developed and applied for the determination of 90Sr and 89Sr in environmental and nuclear samples using various measuring techniques, i.e. beta counting, liquid scintillation spectrometry and mass spectrometry. This paper is intended to give an overview about the development of the radiochemical procedures for the separation of strontium and/or yttrium including the classical procedure based on a series of semi-selective precipitations, the ion exchange and solvent extraction procedures and the recently developed extraction chromatographic ones offering high selectivity. An outlook to the procedures under development aiming the technological separation of strontium from radioactive wastes and process solutions is also given. Nuclear measuring techniques and mass spectrometric techniques will be comparatively evaluated. © 2010 Elsevier Ltd. Source


Vajda N.,RadAnal Ltd. | Kim C.-K.,International Atomic Energy Agency
Journal of Radioanalytical and Nuclear Chemistry | Year: 2010

A great number of analytical methods have been developed and applied for the determination of plutonium isotopes in environmental and nuclear samples using alpha spectrometry. This paper is intended to give an overview about the development of the radiochemical procedures for the separation of plutonium starting with a brief description of the "historic" procedures from the early times of nuclear industry followed by a more detailed discussion of the recent developments from the nineties till 2008. Nuclear measuring techniques i.e. semiconductor alpha spectrometry and liquid scintillation counting are critically discussed. Capabilities of these techniques are compared with those of mass spectrometric techniques. © 2009 Akadémiai Kiadó, Budapest, Hungary. Source


Vajda N.,RadAnal Ltd. | Kim C.-K.,International Atomic Energy Agency
Journal of Radioanalytical and Nuclear Chemistry | Year: 2010

A great number of analytical methods have been developed and applied for the determination of 241Am isotope in environmental and nuclear samples using various measuring techniques, i.e. alpha and gamma spectrometry, liquid scintillation counting and mass spectrometry. This paper is intended to give an overview about the development of the radiochemical procedures for the separation of americium starting with a brief description of the analytical procedures from the "historic" times, followed by a more detailed discussion of the recent developments from the middle of 1990s till 2009 and giving an outlook to the procedures under development aiming the technological separation of americium from radioactive wastes and process solutions for purposes of partitioning of minor actinides. Nuclear measuring techniques and mass spectrometric techniques will be comparatively evaluated. © 2010 Akadémiai Kiadó. Source

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