Determination of 8 Kinds of Aryloxyphenoxypropionate Herbicide Residues in Foods by Dispersive Solid Phase Extration and Gas Chromatography-Tandem Mass Spectrometry

A screening method was proposed for the determination of 8 kinds of aryloxyphenoxypropionate herbicide residues in 12 kinds of food by the technique of dispersive solid phase extration and gas chromatography-tandem mass spectrometry (DSPE-GC-MS/MS), such as soybean, green tea, rice, radish, spinach, peas, garlic, strawberry, bee honey, pork, fish and egg, etc. Pesticides interested were extracted from samples with acetonitrile (saturated by n-hexane) containing 1% acetic acid，and liquid-liquid partition was formed after added anhydrous magnesium sulfate plus sodium acetate， and then a cleanup step followed， known as dispersive solid-phase extraction named QuEChERS method. The aliquot was determined by gas chromatography-tandem mass spectrometry(GC-MS/MS) using external standard method. The linearity of method are between 20 μg•L^-1 and 1 000 μg•L^-1, and the LOQs of pesticides are less than 4 μg•kg^-1. The method is reliable and stable. The recoveries of all pesticides are in the range of 70%—120% at the three spiked levels of 10, 20 and 40 μg•kg^-1 into 12 kinds of food, and the RSDs are all below 13%. The method is selective well with no interference for multiple kinds of foods, especial in the complicated garlic matrix.