Authors:A. Książczak, K. Drożdżewska and H. Boniuk
Thermal degradation of atrazine and its metabolites has been investigated using a thermogravimetric technique(TG) with the
application of three types of crucibles: opened, Knudsen type and labyrinthtype, and non-isothermal DSC method, using hermetically
closed and opened alumina sample pans. The great influence of decomposition conditions (the crucible type) on thermal degradation
was observed. TG analysis showed that the degradation process of atrazine took place in three stages. The increase of amino
groups in triazine ring increases the amount of non-volatile thermal degradation products by association. The presence of
chlorine substituent facilitates the forming of products with low volatility. Hydroxyatrazine decomposes only in one stage
process. The dealkylation process observed in hermetical sample pans (DSC) was two-stage and in open sample pans one-stage
Authors:Maciej Gawlik, Robert Skibiński and Łukasz Komsta
yet. It was found that the main metabolite is O -desmethyl lacosamide with no anticonvulsant activity. Other metabolites, especially from polar fraction, have not been characterized so far [ 25 , 26 ].
The main goal of this study was to
Authors:Vera Faigl, Mónika Keresztes, Alíz Márton, Hedvig Fébel, Margit Kulcsár, Sándor Nagy, Sándor Cseh, László Solti and Gyula Huszenicza
., Fébel, H., Novotni Dankó, G., Magyar, K., Husvéth, F., Solti, L., Cseh, S. and Huszenicza, Gy. (2009): Milk progesterone profiles, blood metabolites, metabolic hormones and pregnancy rates in Awassi ewes treated by gestagen + eCG at the early breeding
Authors:Changmin Shao, Jian Zheng, Junjie Chi, Lijia Jing, Xiufeng Yan and Yang Wang
metabolite of MCPT in rat plasma and tissues via high-performance liquid chromatography (HPLC)/photodiode array detection (PDA) and ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) analysis. Meanwhile, we established a validated
Authors:M. Crevar-Sakač, Z. Vujić, Z. Vujčić, B. Marković and D. Vasiljević
A simple and sensitive liquid chromatography—tandem mass spectrometry method was developed for the quantification of atorvastatin, ortho-hydroxyatorvastatin, para-hydroxyatorvastatin, and atorvastatin lactone in rat plasma. Solid-phase extraction was used for preparation of samples. Rosuvastatin was chosen as an internal standard. Chromatographic separation was achieved on ZORBAX Eclipse C18 Analytical, 4.6 × 100 mm (3.5 μm) column with a gradient mobile phase composed of acetonitrile and 0.1% acetic acid, at a flow rate of 400 μL min−1. The column was kept at constant temperature (25 °C), and autosampler tray temperature was set at 4 °C. The following selected reaction monitoring (SRM) transitions were selected: (m/z, Q1 → Q3, collision energy) atorvastatin (559.47 → 440.03, 22 eV), atorvastatin lactone (541.36 → 448.02, 19 eV), ortho-ohydroxyatorvastatin (575.20 → 440.18, 20 eV), para-hydroxyatorvastatin (575.54 → 440.18, 20 eV), and rosuvastatin (482.25 with selected combination of two fragments 257.77, 31 eV, and 299.81, 35 eV) in positive ion mode. The method was validated over a concentration range of 0.5–20 ng mL−1 for ortho-hydroxyatorvastatin and para-hydroxyatorvastatin and 0.1–20 ng mL−1 for atorvastatin and atorvastatin lactone with excellent linearity (r2 ≥ 0.99). This method demonstrated acceptable precision and accuracy at four quality control concentration levels. The detection limits were 0.1 and 0.13 ng mL−1 for orth-ohydroxyatorvastatin and para-hydroxyatorvastatin, respectively, and 0.05 ng mL−1 for atorvastatin and atorvastatin lactone. All analytes were found to be stable at examined conditions. Validated method was applied for determination of atorvastatin and its metabolites in plasma of experimental animals.
Authors:V. Csomor, R. Laufer, Z. Pöstényi, H. Kalász, E. Adeghate, S. Nurulain, K. Tekes and A. Adem
l-Deprenyl and its major metabolites were subjected to reversed-phase high-performance liquid chromatography (HPLC). The separation was monitored using both ultraviolet (UV) and electrochemical detectors. Ultraviolet absorbance detected l-deprenyl, l-nordeprenyl, l-methamphetamine, and l-amphetamine. Amperometric detection was specific and sensitive to the parent compound (l-deprenyl, a tertiary amine) only. Peaks of the major L-deprenyl metabolites did not give any comparable signal using amperometric monitoring.