| Title: | "Determination of volatile components of green, black, oolong and white tea by optimized ultrasound-assisted extraction-dispersive liquid-liquid microextraction coupled with gas chromatography" |
| Author(s): | Sereshti H; Samadi S; Jalali-Heravi M; |
| Address: | "Department of Chemistry, Faculty of Science, University of Tehran, Tehran, Iran. sereshti@khayam.ut.ac.ir" |
| DOI: | 10.1016/j.chroma.2013.01.029 |
| ISSN/ISBN: | 1873-3778 (Electronic) 0021-9673 (Linking) |
| Abstract: | "Ultrasound assisted extraction (UAE) followed by dispersive liquid-liquid microextraction (DLLME) was used for extraction and preconcentration of volatile constituents of six tea plants. The preconcentrated compounds were analyzed by gas chromatography-mass spectrometry (GC-MS). Totally, 42 compounds were identified and caffeine was quantitatively determined. The main parameters (factors) of the extraction process were optimized by using a central composite design (CCD). Methanol and chloroform were selected as the extraction solvent and preconcentration solvent, respectively .The optimal conditions were obtained as 21 in for sonication time; 32 degrees C for temperature; 27 L for volume of extraction solvent and 7.4% for salt concentration (NaCl/H(2)O). The determination coefficient (R(2)) was 0.9988. The relative standard deviation (RSD %) was 4.8 (n=5), and the enhancement factors (EFs) were 4.0-42.6" |
| Keywords: | Analysis of Variance Caffeine Chloroform/chemistry Gas Chromatography-Mass Spectrometry/*methods Limit of Detection Linear Models Liquid Phase Microextraction/*methods Methanol/chemistry Organic Chemicals/*analysis/isolation & purification Reproducibility; |
| Notes: | "MedlineSereshti, Hassan Samadi, Soheila Jalali-Heravi, Mehdi eng Netherlands 2013/02/05 J Chromatogr A. 2013 Mar 8; 1280:1-8. doi: 10.1016/j.chroma.2013.01.029. Epub 2013 Jan 16" |
