The application of salting-out in the analysis of methoxy-phenolic compounds in Pu-erh Tea

Abstract

This paper presents the application of salting-out in the analysis of methoxy-phenolic compounds in pu-erh tea by using headspace solid microextraction (HS-SPME) combined with gas chromatography mass spectrometry (GC/MS). At first, the influences of extraction and the best extraction condition were investigated, include SPME fibers, extraction time and extraction temperature. Under the optimum condition, the salting-out performances of NH4Cl, KCl, NaCl, MgCl2, Na2SO4, (NH 4)2SO4 and C6H5O 7Na3 were studied. Sodium citrate exhibits the highest extraction efficiency. Compared with unsalted, the total peak area of methoxy-phenolic compounds increased by 2.8 times with sodium citrate added. With C6H5O7Na3, the proposed method affords wide of linearity, good linear regression coefficients (0.992-0.999), detection limits varied from 1.54 to 14.53 ng/g and the relative standard deviations for repeatability were below 10 %. Recovery was ranged from 82.05 to 112.04 % and the relative standard deviations were below 10 %. © Springer-Verlag Berlin Heidelberg 2014.