title: Optimization of headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry for detecting methoxyphenolic compounds in pu-erh tea.
abstract: A method based on headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry was developed for the analysis of volatile methoxyphenolic compounds in pu-erh tea. Six fibers with different polarities were initially evaluated. The 75 μm carboxen/polydimethylsiloxane fiber exhibited the highest extraction efficiency and was selected for further optimization. A Plackett-Burman design was used to screen for the brewing proportion of tea and water, amount of pu-erh tea, ionic strength, extraction time, extraction temperature, desorption time, rate of agitation, and equilibrium time. A Box-Behnken design was then applied to optimize the significant factors. Under optimal conditions, the proposed method affords a wide range of linearity, high linear regression coefficients (0.996-0.999), less than 9.0% repeatability of relative standard deviation, and limits of detection ranging from 2.31 to 21.80 ng/g. The proposed method has satisfactory accuracy, with recoveries of 79.08-113.9%. This method was successfully applied for the analysis of pu-erh tea samples.
authors.affiliation: Key Laboratory of Industrial Fermentation Microbiology Ministry of Education, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, People's Republic of China.
authors.forename: Liping
authors.initials: L
authors.lastname: Du
authors.forename: Chao
authors.initials: C
authors.lastname: Wang
authors.forename: Jianxun
authors.initials: J
authors.lastname: Li
authors.forename: Dongguang
authors.initials: D
authors.lastname: Xiao
authors.forename: Changwen
authors.initials: C
authors.lastname: Li
authors.forename: Yongquan
authors.initials: Y
authors.lastname: Xu
mesh_terms: D004129:Dimethylpolysiloxanes / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D010647:Phenyl Ethers / Q000737:chemistry*; D015203:Reproducibility of Results; D052617:Solid Phase Microextraction / Q000379:methods*; D013662:Tea / Q000737:chemistry*; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D004129:Dimethylpolysiloxanes; D010647:Phenyl Ethers; D013662:Tea; D014867:Water; C013830:baysilon