Simultaneous quantitative determination of major plant hormones in pear flowers and fruit by UPLC/ESI-MS/MS

Plant hormones play a significant role in regulating growth and development during the entire life of a plant, and in response to biotic and abiotic stress. The determination of the concentrations of hormones in flowers and fruit is essential to understanding the role of hormones in the regulation of physiological and biochemical processes associated with flowering and fruit development. Based on high-performance liquid chromatography, coupled with tandem mass spectrometry, we developed and established a novel method to quantify four distinct endogenous hormones through ultra-performance liquid chromatography-tandem mass spectrometry (UPLC/ESI-MS/MS), which achieves higher throughput screening and improved resolution than HPLC or HPLC/ESI-MS/MS. Crude plant extracts were prepared by extraction with extraction solvents i and ii, then purified with a Sep-Pak(TM) C-18 reverse-phase extraction cartridge, and subsequently the purified extracts were analyzed by UPLC/ESI-MS/MS. Plant hormones, comprising indole-3-acetic acid, abscisic acid, gibberellin A(4), and trans-zeatin riboside, were separated and quantified in 6 min. The method was simple, rapid, and precise, and was applied for the determination of plant hormones in pear tissue, with recoveries ranging from 70.11% to 89.84% and relative standard deviations ranging from 4.25% to 14.96%. In conclusion, sample preparation, extraction, purification, and UPLC/ESI-MS/MS conditions were optimized for quantitative analysis of four major plant hormones in pear tissue.