| This dissertation bases on the principle of food security. Applications of modern separation techniques including liquid chromatograph in detection in food security were introduced as well as the new sample pretreatment techniques including solid phase.This dissertation consists of two chapters:Chapter 1: The method for contents determination ofα-acid,β-acid and isoα-acid in hop pellets by two-dimensional high performance liquid chromatography was set up. The analytical column was Acclaim C18 (4.6×150mm,5μm) and photodiode array detector was used. The mobile phase was methanol–water at 1.0 mL/min. Before direct injection sample was dissolved in methanol and filtered. The limit of determination of 5μg/L forα-acid,β-acid and isoα-acid were attained, the recovery was between 83.4%~96.3%,relative standard deviation was between 1.89~6.95.Chapter 2: The method for contents determination of eight kinds of synthetical pigments in cake by two-dimensional high performance liquid chromatography was set up. The analytical column was Acclaim C18 (4.6×150mm,5μm, DIONEX company (America)) at 21℃. The mobile phase was methanol–water (ammonium acetate) at 1.0 mL/min Photodiode array detector was used and the wavelength selected for analysis was 250 nm. Before injection sample was purified and concentrated by solid phase extraction column. The limit of determination of 3~0.25μg/L for Azorubine,Indigotin,Fancy Red,Amaranth, 6.25~0.5μg/mL for lemon-yellow, 50~5μg/mLfor Carmine, 25~2.5μg/mL for Sunset Yellow, 30~2.5μg/mLfor light blue were attained. The recovery was between 70.3%~92.3%,relative standard deviation was between 1.42~7.33. It is a simple, rapid and exact method.Whether two-dimensional high-performance liquid chromatography for the particles hopα-acids,β-acids, iso-α-acid detection, or used in the synthesis of pigment cake tests are simple, rapid, and accurate.
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