Quantitative analysis of acrylamide in tea by liquid chromatography coupled with electrospray ionization tandem mass spectrometry.

An effective sample preparation procedure was optimized and a liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the quantitative analysis of acrylamide in tea. [(13)C3]-acrylamide was used as internal standard. Acrylamide was extracted at 25°C for 20min by 10ml water followed by 10ml acetonitrile, and then 4g of magnesium sulfate and 0.5g of sodium chloride were added to the above mixture under stirring thoroughly. In order to increase the response of acrylamide, 9ml acetonitrile layer was taken and concentrated to 0.5ml. Solid-phase extraction with an Oasis MCX cartridge was carried out for clean-up. The limit of detection (LOD) and limit of quantification (LOQ) were 1 and 5ng/ml, respectively. The recovery efficiency of the extraction procedure ranged between 74% and 79%. The levels of acrylamide in 30 tea samples were less than 100ng/g. Black, oolong, white and yellow tea samples had quite low acrylamide contents (<20ng/g). Higher acrylamide levels occurred in baked, roasted, and one sun-dried green tea samples (46-94ng/g).