Comparison of Determination Methods for Phthalates by Liquid-Phase Microextraction Coupled Gas Chromatograph-Mass spectrometry

Three kinds of liquid-phase microextraction(LPME) methods,including static direct-immersed LPME(SDI-LPME),dynamic direct-immersed LPME(DDI-LPME) and hollow fiber LPME(HF-LPME) coupled with gas chromatograph-mass spectrometry(GC-MS) for the determination of phthalic acid esters(PAEs) in drink were compared.The optimized conditions of the three kinds of method were as follows:for SDI-LPME,the samples were extracted with 2.0 μL of the mixture of toluene and cyclohexane(3∶1,V/V) for 40 min at 500 r/min rotating speed;for DDI-LPME,the samples were extracted with 2.0 μL toluene at 400 r/min rotating speed and whipping 25 times at a rate of once a minute;for HF-LPME,the samples were extracted with 20 μL octyl alcohol for 30 min at 800 r/min rotating speed.The linear ranges and the relative standard deviation of the three methods are 0.50-500 μg/L(3.0%-13.7%),0.100-10.0 μg/L(17.3%-23.1%) and 0.100-100.0 μg/L(8.1%-15.5%),respectively,for the determination of dimethyl phthalate(DMP),diethyl phthalate(DEP),dibutyl phthalate(DBP) and butyl benzyl phthalate(BBP),and the standard addition recoveries were 89.5%-115.2%,70.6%- 91.0%,91.5%-112.8%,respectively,in real drink sample analysis.