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J Chromatogr A

Title:		"A comparative study of volatile components in green, oolong and black teas by using comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry and multivariate data analysis"
Author(s):		Zhang L; Zeng Z; Zhao C; Kong H; Lu X; Xu G;
Address:		"CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China"
Journal Title:		J Chromatogr A
Year:		2013
Volume:		20130619
Issue:
Page Number:		245 - 252
DOI:		10.1016/j.chroma.2013.06.022
ISSN/ISBN:		1873-3778 (Electronic) 0021-9673 (Linking)
Abstract:		"The difference of volatile components in green, oolong and black teas was studied by using comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GCxGC-TOFMS). Simultaneous distillation extraction was proved to be a suitable technique to extract the analytes with interest. A total of 450 compounds were tentatively identified with comparison to the standard mass spectra in available databases, retention index on the first dimension and structured chromatogram. 33 tea samples, including 12, 12 and 9 samples of green, oolong and black tea were analyzed by using GCxGC-TOFMS. After peak alignment, around 3600 peaks were detected. Partial least squares - discriminant analysis and hierarchical cluster analysis were used to classify these samples, then non-parametric hypothesis test (Mann-Whitney U test) and the variable importance in the projection (VIP) were applied to discover the key components to distinguish the three types of tea with significant difference amongst them. 74 differential compounds are defined to interpret the chemical differences of 3 types of tea. This study shows the power of GCxGC-TOFMS method combined with multivariate data analysis to investigate natural products with high complexity for information extraction"
Keywords:		Cluster Analysis Gas Chromatography-Mass Spectrometry/*methods Multivariate Analysis Reproducibility of Results Tea/*chemistry Volatile Organic Compounds/*analysis GCxGC-TOFMS Simultaneous distillation extraction Structured chromatogram Tea Volatile compo;
Notes:		"MedlineZhang, Lei Zeng, Zhongda Zhao, Chunxia Kong, Hongwei Lu, Xin Xu, Guowang eng Comparative Study Research Support, Non-U.S. Gov't Netherlands 2013/07/11 J Chromatogr A. 2013 Oct 25; 1313:245-52. doi: 10.1016/j.chroma.2013.06.022. Epub 2013 Jun 19"