| An internal standard quantitative method was developed for the simultaneous determination of 24 phthalate esters(PAEs) in sea foods by gas chromatography-mass spectrometry(GC-MS).1.0 g Sample was taken into glass centrifuge tube,followed by adding 100 μL internal standard solution(10 mg/L),0.5 g NaCl and 5 mL acetonitrile-acetate ester(1∶1) extraction solution.The solution was mixed for 1 min,and extracted by ultrasonic for 5 min and centrifuged for 5 min at 4 000 r/min.The extraction step was repeated with 3 mL acetonitrile-acetate ester.The two extracted solvents were concentrated to 1-2 mL,and then cleaned up through a glass Florisil SPE column.The analyses of 24 PAEs were carried out by GC-MS under selected ion monitoring(SIM) mode.The results showed that 24 PAEs had good linear relationships(r＞0.999) between 0.05 mg/L and 10.0 mg/L.The limits of quantitation(LOQs) of 24 PAEs were in the range of 1-500 μg/kg,and the limits of detection(LODs) were in the range of 0.1-100 μg/kg.The average recoveries of 24 PAEs in fish and prawn samples ranged from 73% to 120%,with relative standard deviations(RSDs,n=6) of 2.0%-19.7%.The method was well suitable for the determination of PAEs in sea foods with its high sensitivity and precision. |