| A liquid chromatography-tandem mass spectrometric（LC-MS/MS） method was developed for the simultaneous determination of indole-3-butyric acid（IBA），indole-3-acetic acid （IAA） and its 7 amino acid conjugates including IAA-Asp,IAA-Ala,IAA-Val,IAA-Trp,IAA-Leu,IAA-Ile and IAA-Phe in rice．The sample was extracted with 80% methanol for 12 h at 4 ℃.The extract was cleaned up on an Oasis MAX cartridge（60 mg×3 mL）,and eluted with methanol contained 05% formic acid.9 analytes were separated on a C18 column （1.8 μm,100 mm×2.1 mm i.d.） using 5 mmol/L ammonium formate（A） -acetonitrile（B） as mobile phase by gradient elution.The analytes were detected by positive-ion electrospray ionization-mass spectrometry under multiple reaction monitoring（MRM） mode.The recoveries of 9 analytes from the matrixes of root,sheath,leaf and seed in rice tissue ranged from 75% to 106% with relative standard deviations（RSDs） of 3.6%-15.2%.The detection limits(S/N=3) ranged from 0.01 μg/kg to 25 μg/kg.The method was sensitive and reliable,and could meet the requirements for quantification of auxins and their amino acid conjugates in rice at the physiological level. |