Determination of 7 Plant Growth Regulator Residues in Orange by Solid Phase Extraction and Liquid Chromatography-Tandem Mass Spectrometry

KeyWord:solid phase extraction£¨SPE£©  high performance liquid chromatography-tandem mass spectrometry£¨HPLC-MS/MS£©  plant growth regulator£¨PGR£©  orange  residue

Abstract:

      A liquid chromatography-tandem mass spectrometric£¨LC-MS/MS£© method with solid phase extraction was developed for the determination of 7 plant growth regulators£¨PGRs£©£¬including 2,4-dichlorophenoxyacetic acid£¬gibberellic acid£¬indole-3-butyric acid£¬¦Á-naphthaleneacetic acid£¬4-fluorophenoxyacetic acid£¬4-chlorophenoxyacetic acid and indole-3-acetic acid£¬in orange.The samples were extracted with acetonitrile£¨contain 2% formic acid£©£¬and cleaned up on a Poly-Sery MAX.The extract was eluted with 4% formic acid in methanol£¬then evaporated with a stream of nitrogen to near dryness£¬and redissoved with acetonitrile-water£¨1¡Ã9£©. The targeted compounds were separated on a Phenomenex Gemini-NX 5u C18 110A£¨2.0 mm i.d.¡Á150 mm£¬5.0 ¦Ìm£©£¬and determined by LC-MS/MS under MRM mode with the matrix-matched external standard method.The results indicated that the calibration curves were linear in the certain concentration range with correlation coefficients greater than 0.99.The limits of detection£¨LODs£¬S/N>3£© were in the range of 0.3-3.5 ¦Ìg/kg and the limits of quantitation£¨LOQs£¬S/N>10£© were 5.4-57.7 ¦Ìg/kg.The recoveries of 7 PGRs in orange at three spiked levels ranged from 79.6% to 110.3% with relative standard deviations£¨RSDs£© of 3.1%-10.0%.The established method was simple and sensitive£¬and could meet the requirements for simultanous analysis of PGRs in amphisarcas.