The invention discloses a method for determining the residue of
triazine pesticide in tea by dispersive liquid-liquid micro-extraction and magnetic
solid-phase extraction. The method is a tea sample
pretreatment method. The tea sample
pretreatment method comprises the following steps of: putting 0.5 g of sample into a 10ml
polypropylene centrifugal tube with a stopper, adding 3 ml of
acetonitrile, shaking, centrifuging, moving supernatant to another centrifugal tube, adding 3 ml of
acetonitrile into residue, repeatedly executing the steps, and combining extracting solutions which are obtained at two times;
drying by
nitrogen, moving 5 ml of water, whirling, adding 20 microliters of n-octyl
alcohol, shaking, adding 200 microliters and 20 mg / ml of magnetic nano particle solution, shaking, attracting magnetic nano particles to the wall of the centrifugal tube by using a
magnet, and removing
effluent; and adding 50 microliters of
methanol into the centrifugal tube, whirling, attracting the magnetic nano particles to the bottom of the centrifugal tube by using the
magnet, taking the solution out by using a microsyringe, and performing efficient liquid
chromatography-
mass spectrometry analysis. The method is easy and convenient to operate, short in analysis time, low in cost, high in sensitivity and applicable to detection of
pesticide residue of the tea.