A method for simultaneous determination of 20 Perfluorinated alkyl substances ( PFAS) in animal liver using QuEChERs and HPLC_MS/MS technique was developed. The samples were extracted with 0. 1%hydrochloric acetonitrile and cleaned up with C18 , N_Propylethylendiamine ( PSA ) and graphitized carbon blacks ( GCB ) . The analytes were separated by a reversed phase C18 column and gradiently eluted with a mixed solution of 5 mmol/L ammonium acetate methanol and 5 mmol/L ammonium acetate. The samples were quantified using isotope internal standard and external standard with the matrix matched standard calibration curve method. Good linearity was obtained for all the 20 PFAS at the concentration of 0. 1-10 μg/L with the linear correlation coefficients more than 0. 9995. The limits of detection (LOD) and the limits of quantification ( LOQ) for PFAS were 0. 05-0. 2 μg/kg and 0. 4-0. 5 μg/kg, respectively. The recoveries at three different concentration levels ( 0 . 5 , 2 and 5 μg/kg ) were in the range of 70 . 3% -108 . 1%. The repeatability expressed as relative standard deviations (RSD) was ranged from 2. 1% to 11. 9% (n=6).

An analytical method based on high performance liquid chromatography tandem mass spectrometry has been developed for the simultaneous determination of 20 anti-obesity drugs ( fenfluramine, phenylpropanolamine, sibutramine, sertraline, rimonabant, bupropion, citalopram, fluoxetine, benfluorex, topiramate, zonisamide, caffeine, phenolphthalein, emodin, indapamide, bumetanide, torasemide, triamterene, orlistat, phenformin). that were extracted from various weight-loss functional foods by ethanol-acetone(7:3, V/V)and purified by primary secondary amine (PSA) and octadecyltrimethoxysilane(ODS) under ultrasonication. The analysis was carried out on HPLC-MS /MS by electrospray ionization using multiple reaction monitoring after the chromatographic separation on Waters Atlantis T3 (3 μm, 150 mm × 2. 1 mm) column. Identification was achieved by the retention time and the ion ratio, quantification was done by the external standard method. The limits of detection for the appetite suppressants were 0. 05-3. 0 mg/kg. The mean recoveries at the three spiked levels were 67 . 1%-101 . 4%, with the intra-day precision less than 10%and the inter-day precision less than 15%. The method is reliable, accurate, reproducible and suitable for the determination of the anti-obesity drugs in different weight-loss functional foods.