Determination of 23 phthalate esters in food by solid-phase extraction coupled with gas chromatography-mass spectrometry

A method for the simultaneous determination of 23 phthalate esters in food samples by solid-phase extraction coupled with gas chromatography-mass spectrometry (SPE-GC-MS) was developed and evaluated. The samples were extracted with hexane or acetonitrile, and cleaned up with a glass ProElut PSA SPE column. The identification and quantification were performed by GC-MS in selected ion monitoring (SIM) mode. The extraction processes of different foods were investigated. The calibration curves of phthalate esters showed good linearity in the range of 0.05 - 5 mg/L (0.5 - 5 mg/L for diisononyl phthalate (DINP), diisodecyl-phthalate (DIDP)) with the correlation coefficients (r) between 0.984 8 and 0.999 6. The limits of detection of phthalate esters in food samples ranged from 0.005 to 0.05 mg/kg (S/N = 3) and the limits of quantification ranged from 0.02 to 0.2 mg/kg (S/N = 10). The average recoveries of 23 analytes spiked in 10 kinds of food matrices ranged from 77% to 112% with the relative standard deviations (RSDs, n = 6) of 4.1% - 12.5%. The method is suitable for the determination of 23 phthalate esters simultaneously in foodstuffs with easy operation, high accuracy and precision.