A method was developed for the determination of diethyl aminoethyl hexanoate (DA-6) residues in apples by gas chromatography-mass spectrometry (GC-MS) combined with improved QuEChERS. The samples were first extracted with warm water, then, the extract was subjected to liquid-liquid re-extraction with dichloromethane, followed by rotary evaporation concentration. The residues were cleaned up with primary secondary amine (PSA). The analytes were separated on an HP-5 capillary column and detected using an EI source in the SIM mode. The recoveries ranged from 74.1% to 84.2% at three spiked levels, with relative standard deviations (RSDs) between 1.5% and 4.1%. The limit of detection and limit of quantification were 0.0024 mg/kg and 0.008 mg/kg, respectively. The developed method is sensitive, and practically applicable for the determination of DA-6 residues in apple samples.
Keywords: QuEChERS; apple; diethyl aminoethyl hexanoate (DA-6); gas chromatography-mass spectrometry (GC-MS).