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Determination of 61 pesticide residues in concentrated apple juice using ultra performance liquid chromatography-tandem mass spectrometry

An ultra performance liquid chromatography tandem mass spectrometric method( UPLC-MS / MS) has been developed for the determination of 61 pesticide residues in concentrated apple juice( AJC). The sample was deluted with disodium hydrogen phosphate buffer solution,and adjusted p H to 8 ~ 9,and then extracted by acetonitrile. The extraction solution was cleaned by a N-propyl ethylenediamine( PSA) solid-phase extraction column. UPLC was performed on a ACQUITY UPLC HSS T3 column using a gradient methanol-aqueous solution containing 0. 1% formic acid system as mobile phase,and MS / MS was performed with multiple reaction monitoring( MRM) mode. Quantitation was carried out using an external standard method. The calibration curves of the 61 pesticides were linear in the range of 0. 01 ~ 0. 5 mg / L with linear correlation coefficients not less than 0. 98,and the detection limits were between 0. 23 × 10-3mg / kg to 2. 9 × 10-3mg / kg. The average recoveries of all the pesticides were in the range of 77. 5% to 103. 5% at three spiked levels of 0. 01,0. 02 and0. 05 mg / kg in concentrated apple juice,and the relative standard deviations were lower than 15%. The sensitivity,accuracy and repeatability of the method all meet the requirements of pesticide residual analysis.