Study On Simultaneous Extraction Of Multiple-phytohormones And Its Application In Plant Analysis

Along with the advancement of science and technology,great improvements have also been achieved in agricultural production,which led to the study on plant growth regulators,particularly phytohormones.Phytohormones are small signaling molecules that play crucial roles in the regulation of plant growth and development.According to numerous physiological and genetic studies,each class of phytohormone functions in different developmental and growth processes.Moreover,multiple phytohormones act through signaling networks and often impact the same biological process by additive,synergistic or antagonistic actions.Therefore,to better understand the molecular mechanisms and interactions of phytohormones in complex signaling networks,it is necessary to investigate their concentration,diversification,spatial and temporal distribution.Particularly,considerable gaps in our knowledge and understanding of the temporal distribution of multiple-phytohormone such as acidic,basic,and neutral phytohormone still exist.This type of study requires the ability to accurately and efficiently determine multiple phytohormones simultaneously.Due to the low content of phytohormones in plant samples,and their complex matrix and structural diversity,it remains a challenge to develop improved methods of determining multiple phytohormones.In this dissertation,(1)Several CFs-IL with different functional groups were synthesized on structural features of phytohormones.(2)The extraction performance of diverse CFs-IL on multiple phytohormones was studied with adsorption specificity.(3)A novel CFs-IL-SPME method was developed for simultaneous determination of multiple phytohormones in tomato samples by using LC-MS/MS.(4)The temporal distribution of phytohormones in strawberry samples was studied.The main work and achievements of this dissertation are outlined as follows.1)Novel solid-phase microextraction(SPME)fibers that can simultaneously extract multiple-phytohormones were prepared.To this,ionic liquids were designed based on structural features of phytohormones by considering the hydrophobic,electrostatic,and π-π interactions and hydrogen bonding,and successfully synthesized through nucleophilic substitution reactions of haloalkane and purified by using preparative chromatography.Synthesized ionic liquids were confirmed by characterizing with ESI-MS and 1H NMR.And also,carbon fibers were modified with prepared ionic liquids through covalent functionalization by amidation reaction to form carbon fibers-ionic liquid(CFs-IL)that can use as SPME fiber.The characterization of CFs-IL with FTIR,XPS,and SEM together confirmed the successful modification of CFs with ionic liquid.2)The extraction behavior of prepared CFs-IL on multiple phytohormones was investigated with adsorption specificity.The extraction behavior was explained by hydrophobic,π-π and electrostatic interactions and hydrogen bonding between analytes and sorbents,which provided SPME fiber to extract multiple-phytohormones simultaneously.And also,LC-ESI-QQQ mass spectrometry was established for the analysis of multiple-phytohormones.3)Basing on prepared CFs-IL fibers,a novel SPME method for quantification of multiple-phytohormones was developed,coupled with liquid chromatography-tandem mass spectrometry(LC-MS/MS).The proposed method was successfully applied to the simultaneous determination of 13 phytohormones in a tomato sample to achieve a low LOD,good linearity range,and reliable accuracy and precision.4)CFs-IL-SPME-LC-MS/MS method for quantification of multiple-phytohormones in strawberry samples was developed,and the change in the level of phytohormones was studied during different developmental stages in strawberry.Basing on obtained temporal distribution,the functions and role of phytohormones in strawberry were explained compared with previous reports.