Green Tea Research Today is a free monthly online journal that collates and summarizes the latest research about Green Tea, including details on benefits, antioxidants, weight loss, diet, side effects. | ||||||||
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Application of head-space solid-phase microextraction coupled to comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry for the determination of multiple pesticide residues in tea samples.Schurek J, Portolés T, Hajslova J, Riddellova K, Hernández F Institute of Chemical Technology Prague, Faculty of Food and Biochemical Technology, Department of Food Chemistry and Analysis, Technická 5, Prague 6, 16628, Czech Republic. A new method has been developed to detect 36 pesticides that may contaminate tea samples (green, black and fruit tea). The hyphenation of solid-phase microextraction in head-space mode with a comprehensive two-dimensional gas chromatography coupled with high-speed time-of-flight mass spectrometry (HS-SPME-GCxGC/TOF MS) proved to be a quick alternative to conventional GC/MS methodology which employs solvent-based extraction. The key parameters for controlling HS-SPME performance were optimized, including fiber coating type, temperature and absorption time settings and tea matrix modification by adding water. Quantification was carried out using matrix-matched calibration. The repeatability of measurements, expressed as relative standard deviation (R.S.D.), was less than 24% for all analytes. The limits of quantification ranged from 1 to 28 microgkg(-1). The optimized method was applied to analyze real life samples obtained from a retail market. Results generated by the new SPME procedure and those obtained by using a conventional one involving ethyl acetate extraction and high-performance gel permeation chromatography (HPGPC) clean up agreed with each other for positive (containing residue) samples. Published 10 March 2008 in Anal Chim Acta, 611(2): 163-72.
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