Ionic liquid-based single-drop microextraction coupled with ultra-high performance liquid chromatography for determination of five phthalate esters in food plastic packaging materials

Ionic liquid single-drop microextraction coupled with ultra-high performance liquid chromatography(IL-SDME-UPLC)was developed for extraction and determination of five phthalate esters(PAEs)from food plastic packaging materials. Several important influencing factors on IL-SDME extraction efficiency were investigated,such as the type of ionic liquid,amounts of extraction solvent,extraction time and temperature and salt solution concentration. The results indicated that the optimal experimental conditions were reached under 30 μL 1-octyl-3-methylimidazolium hexafluorophosphates(C₈MIMPF₆)as extraction solvent without adding salt after oscillation 5 minutes at 25 ℃. The above-mentioned optimal method was successfully applied to the detection of the five PAEs in oilcan and beverage bottle. The results showed excellent linearity at 2~100 μg/mL concentration rang for the five PAEs. The coefficients of correlation were no less than 0.999 and the limits of detection ranged from 0.3 μg/mL to 0.92 μg/mL(S/N=3). The recovery rates of five PAEs at three different spiked levels of 10,20,30 μg/mL were up to 37.42%~43.50% of DMP,65.04%~76.90% of DBzP,67.22%~79.88% of DBP,77.60%~89.82% of DCHP and 81.07%~87.62% of DOP with RSD in the range of 0.01%~6.66%(n=3),respectively. The method was suitable to determine PAEs in food plastic packaging materials with environment-friendly characterization,convince,rapid and high operability.