[Determination of four plant growth regulator residues in amphisarcas by high performance liquid chromatography-tandem mass spectrometry].

A high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for the determination of the plant growth regulator (PGR) (paclobutrazol, forchlorfenuron, isopentennyladenine and 6-benzylaminopurine) residues in amphisarcas. The sample was extracted with acetonitrile, then cleaned up by MCX solid phase extraction. The HPLC separation was performed on an Agilent XDB-C18 column with 5 mmol/L ammonium acetate solution and acetonitrile containing 0.1% (volume percentage) formic acid as the mobile phases in a gradient elution mode. The PGRs were determined by MS/MS in positive electrospray ionization mode, and quantified by matrix-matched external standard method. The calibration curves showed good linearity in each range with correlation coefficients greater than 0.999. The limits of quantification (LOQs, S/N > 10) were 0.04-1.35 g/kg and the limits of detection (LODs, S/N > 3) were 0. 01-0 41 microg/kg for the four PGRs spiked in cucumber and apple. The recoveries of the four PGRs spiked at three levels ranged from 81.0% to 93.%, with the relative standard deviations (RSDs) of 3.5%-9.5%. The sensitivity, accuracy and precision of the method meet the technical standards of the pesticide determination. Therefore the method can be applied to the determination of the four PGRs in amphisarcas.