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Nowadays, chromatographic methods coupled with mass spectrometry are the most commonly used tools in metabolomics studies. These methods are currently being developed and various techniques and strategies are proposed for the profiling analysis of biological samples. However, the most important thing used to maximize the number of entities in the recorded profiles is the optimization of sample preparation procedure and the data acquisition method. Therefore, ultra high performance liquid chromatography coupled with accurate quadrupoletime- of-flight (Q-TOF) mass spectrometry was used for the comparison of urine metabolomic profiles obtained by the use of various spectral data acquisition methods. The most often used method of registration of metabolomics data acquisition – TOF (MS) was compared with the fast polarity switching MS and auto MS/MS methods with the use of multivariate chemometric analysis (PCA). In all the cases both ionization mode (positive and negative) were studied and the number of the identified compounds was compared. Additionally, various urine sample preparation procedures were tested and it was found that the addition of organic solvents to the sample noticeably reduces the number of entities in the registered profiles. It was also noticed that the auto MS/MS method is the least efficient way to register metabolomic profiles.
Content available remote A study of photodegradation of quetiapine by the use of LC-MS/MS method
Open Chemistry
tom 10
nr 1
Photodegradation of quetiapine under UVC irradiation in methanol solution was investigated and structural elucidation of its photodegradation products was performed with the use of the reversed phase UHPLC system coupled with accurate mass hybrid ESI-Q-TOF mass spectrometer. During one run all essential data for the determination of photodegradation kinetics and for the structural elucidation of the products was collected with the use of auto MS/MS mode. Five degradation products were found and their masses and formulas were obtained with high accuracy (0.26–5.02 ppm). For all the analyzed compounds, MS/MS fragmentation spectra were also obtained allowing structural elucidation of the unknown degradation products and indicating photodegradation pathways of quetiapine. The main photodegradation product was identified as 2-[2-[4-(5-oxidodibenzo[b,f][1,4]thiazepin-11-yl)-1-piperazinyl]ethoxy]-ethanol and the photodegradation reaction yields the first-order kinetics with the rate constant k = 0.1094 h−1.
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