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Tolgyesi L.,Eotvos Lorand University | Tolgyesi L.,Kromat Ltd. Co. | Kele P.,Eotvos Lorand University | Torkos K.,Eotvos Lorand University
Chromatographia | Year: 2010

A quantitative acetonitrile extraction with dispersive solid-phase clean-up and subsequent high performance hydrophilic interaction liquid chromatography-atmospheric pressure electrospray ionization mass spectrometry (HILIC-ESI-MS-MS) analysis is outlined for the determination of propylenethiourea (PTU, 4-methylimidazolidine-2-thione), the main degradation product of propylenebisdithiocarbamate (PBDC). In the present study, the quick, easy, cheap, effective, rugged and safe method (QuEChERS) methodology was adopted for the extraction of PTU from tomato matrix. The synthesis and impurity profiling of a new internal standard compound (4,5-dimethylimidazolidine-2- thione) is also reported, which was used instead of tris(1,3-dichlorisopropyl) phosphate due to poor ionization at elevated acetonitrile levels. The effect of chromatographic parameters on the HILIC separation and MS detection was studied. Coupling of hydrophilic interaction liquid chromatography with mass spectrometric detection was advantageous not only in view of separation and ionization efficiency but also in direct injection of the QuEChERS extract without the need for solvent exchange. © 2010 Vieweg+Teubner Verlag | Springer Fachmedien Wiesbaden GmbH. Source


Jankovics P.,National Institute of Pharmacy | Varadi A.,Semmelweis University | Tolgyesi L.,Eotvos Lorand University | Tolgyesi L.,Kromat Ltd. Co. | And 3 more authors.
Forensic Science International | Year: 2012

3-Naphthoyl- and 3-phenylacetylindoles represent a group of substances of cannabimimetic activity with affinities - strongly influenced by their functional groups - to cannabinoid receptors CB1 and CB2. Some of them have been described as ingredients of herbal blends also known as "smart products" by several research groups. Recently further cannabimimetic substances possessing new chemical structures like benzoylindoles and adamantoylindoles have emerged. In Hungary, two powder samples were seized by the authorities and identified as 1-pentyl-3-(2-iodobenzoyl)indole (AM-679) and 1-pentyl-3-(1-adamantoyl)indole. Structure elucidation was carried out by LC-UV-MS/MS, LC-TOF-MS, GC-MS and NMR. The benzoylindole AM-679 is a known agonist of cannabinoid receptors while the adamantoylindole derivative also carries chemical features typical for cannabimimetics. It is thus assumed that both substances might be detected in "smart products" in the future. © 2011 Elsevier Ireland Ltd. Source


Tolgyesi A.,Food Toxicology National Reference Laboratory | Tolgyesi L.,Eotvos Lorand University | Tolgyesi L.,Kromat Ltd. Co. | Sharma V.K.,Florida Institute of Technology | And 2 more authors.
Journal of Pharmaceutical and Biomedical Analysis | Year: 2010

A new method was developed to identify and quantify corticosteroids (prednisolone, methylprednisone, flumetasone, dexamethasone, and methylprednisolone) in raw bovine milk by liquid chromatography-tandem mass spectrometry (LC-MS/MS) utilizing mixed-mode polymeric strong cation exchange and reversed-phase (MCX) solid-phase extraction (SPE) to reduce ion effects in a multimode ion (MMI) source. The main advantage of this method over other commonly used methods includes the use of a single SPE cartridge with a low volume for sample preparation and fast separation on the HPLC system with reduced ion suppression. This study is the first to report the determination of methylprednisone, a metabolite of methylprednisolone, in bovine milk. This method was validated in accordance with the European Union (EU) Commission Decision 2002/657/EC. The recoveries vary between 90% and 105%. The within-laboratory reproducibility (precision) is less than 30%. The decision limits and detection capabilities were calculated along with LODs, which ranged from 0.02 to 0.07 μg/kg. The method was further enhanced by its successful adaptation to other LC-MS/MS systems equipped with the newly developed ion source, Agilent Jet Stream (AJS). After optimization of the AJS ion source and MS parameters, even lower LOD values were achieved (0.001-0.006 μg/kg) for the corticosteroids. Analytical results obtained with the AJS were characterized by an enhanced area response and similar noise level comparable to those obtained with conventional orthogonal atmospheric ionization (API). © 2010 Elsevier B.V. Source


Jankovics P.,National Institute of Pharmacy | Varadi A.,Semmelweis University | Tolgyesi L.,Eotvos Lorand University | Tolgyesi L.,Kromat Ltd. Co. | And 3 more authors.
Forensic Science International | Year: 2011

A fast and simple LC-MS/MS method was developed for screening mephedrone, butylone, methylenedioxypyrovalerone (MDPV), flephedrone, methylone and methedrone in bulk powder samples. Samples were separated on a reverse phase column using gradient elution with mixtures of water, acetonitrile and formic acid. After optimization a limit of detection of about 2ngmL-1 was achieved using multiple reaction monitoring (MRM) mode. Total run time was less than 8min. Typical fragmentation characteristics of the studied compounds are discussed. The method was successfully applied to several unknown bulk powder samples seized by the Hungarian Customs and Finance Guard. One of the samples contained the new designer drug 4'-methylethcathinone (4-MEC), which was identified and characterized by LC-MS/MS, NMR, FT-IR and LC-TOF-MS techniques. The method is also deemed to be applicable for the screening of simple dosage forms such as tablets and capsules. © 2011 Elsevier Ireland Ltd. Source


Bartok T.,Cereal Research Non Profit Ltd. | Bartok T.,FumoPrep Ltd. | Tolgyesi L.,Eotvos Lorand University | Tolgyesi L.,Kromat Ltd. Co. | And 6 more authors.
Rapid Communications in Mass Spectrometry | Year: 2010

Fumonisin mycotoxins which are hazardous to humans and animals were produced in a Fusarium verticillioides-infected solid rice culture. To decrease the possibility of the formation of artifacts, the fumonisins were analysed by reversed-phase high-performance liquid chromatography/electrospray ionization time-of-flight (RP-HPLC/ESI-TOFMS) and ion trap mass spectrometry (RP-HPLC/ESI-ITMS) immediately after the extraction of the culture material, without any further sample clean-up. The fumonisin isomers were separated by using a flat gradient on a special, high-coverage C18, narrow-bore HPLC column (YMC-Pack J'sphere ODS H80) suggested for the separation of structural isomers by the manufacturer. Exact mass measurements (TOFMS) of the protonated molecules and extraction of the ion chromatogram corresponding to the empirical formula (C34H59NO15) of FB1 toxins led to the identification of 29 peaks and shoulders, including those of FB1. The FB1 toxin and 28 of its isomers were also detected by ITMS after separation with RP-HPLC. The characteristic m/z values of the product ions, including the backbones obtained by ITMS2, undoubtedly indicated the structures of the FB1 isomers for 28 peaks and shoulders. In the MS2 spectra of the protonated molecules of the FB1 isomers, with some exceptions, 15 characteristic product ions including the hydrocarbon backbone at m/z 299 were observed. The abundance ratio of the cation at m/z 299 ranged up to 5.8%. The relative quantities of the isomers found in the sample extract were expressed as percentages of the FB1 content (0.001-0.579%). The total amount of the 28 FB1 isomers was 2.803% of the quantity of FB1 that is important from the aspect of food and feed safety. © 2009 John Wiley & Sons, Ltd. Source

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