Rapid determination of 14 phthalate esters in corn by QuEChERS-based gas chromatography/mass spectrometry method

A modified QuEChERS method was developed for the simultaneous determinationn of 14 phthalate esters(PAEs)in corn prior to gas chromatography-mass spectrometry(GC-MS)analysis. All of the PAEs in corn samples were extracted into acetonitrile and salted out by anhydrous MgSO₄ and NaCl. Then,the PAEs in the supernatant after clean-up by primary secondary amine(PSA),octadecyl silica(C₁₈),and graphitized carbon black(GCB)were subjected to GC-MS analysis. External standard quantification was used to determine the extraction efficiency of each sample. As a result,14 PAEs possessed an excellent linear relation by using matrix-matched curve under 1~500 μg/L,and the correlation coefficients were 0.9945~0.9995.The recoveries of 14 PAEs in corn matrixes at three spiked levels of 15,150 and 500μg/kg ranged from 80.0% to 109.8% with relative standard deviations below 9.0%. The LODs and LOQs for PAEs,based on S/N of 3 and 10,ranged from 0.1 to 2.5 μg/kg and 0.13 to 5.0 μg/kg,respectively. The applicability of the method was properly validated using six corns,and the results revealed that the dimethyl phthalate(DMP),diethyl phthalate(DEP),diisobutyl phthalate(DIBP),dibutyl phthalate(DBP),and bis(2-methoxyethyl)phthalate(DEHP)were detected in all the samples. The content of PAEs is lower than the standard of GB. Overall,the developed QuEChERS-GC/MS method could be considered as a promising method for routine monitoring of PAEs residue in corn since the procedure was easy,fast,and effective.