Application of Single Drop Microextraction in the Determination of Phthalate Esters in Food by Gas Chromatography-Mass Spectrometry
微滴液相微萃取技术用于气相色谱-质谱法测定食品中的酞酸酯

A novel, simple, fast and environment-friendly method based on single drop microextraction (SDME) was developed for the determination of phthalate esters in food by gas chromatography-mass spectrometry (GC-MS). The effects of the nature of organic solvents, microdrop volume, the depth of microdrop in sample solution, extration time and stirring rate on the extraction efficiency were investigated separately. The optimal SDME conditions, 2.0 microL of toluene, 0.75 cm of the depth of microdrop, 1 000 r/min of stirring rate and 20 min of extraction time, were obtained and used for the analysis of dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), dioctyl phthalate (DOP) and diethylhexyl phthalate (DEHP) in food. At first, a sample was dissolved with de-ionized water and then extracted with ultrasonication for 15 min. Then, it was filtrated and the solution was extracted and concentrated by a single drop of a solvent. Finally, it was analyzed by GC-MS. The reproducibility, linearity, recovery, and limit of detection of the method were studied. The results showed that the limits of detection (LOD) were between 25 ng/L and 0.8 mg/L. The overall recoveries were 87.1% - 114.4% with the relative standard deviations of 4.9% - 11.6%. This method has been successfully applied to the analysis of food samples.