The Preparation and Application of Reversed-phase and Ion-exchange Mixed-mode Stationary Phases by Mixing Disilylation Reagents

Author:Song Qing Guo

Supervisor:bai quan

Database:Doctor

Degree Year:2019

Download:23

Pages:164

Size:4695K

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The mixed-mode chromatography(MMC)is especially suitable for the separation of complex samples because it can provide multiple separation mechanisms and has unique separation selectivity.The density,proportion and chromatographic characteristics of MMC stationary phase are often difficult to adjust.Aimed at the problems existed in the traditional prepare method for MMC stationary phase,this paper has prepared several MMC stationary phase based on mixing disilylation reagents.Furthermore,the preparation method to adjust the polarity and charge of the surface of MMC stationary phase was further investigated.This paper mainly consists of the following five parts:1.The preparation and application of reversed phase/weak anion exchange mixed-mode chromatographic stationary phase: A kind of RP/WAX MMC stationary phase named as OTAS was prepared based on the method of mixing disilylation reagents.By controlling the molar ratios of ODS and EPS during copolymerization,the surface polarity,charge characteristics and chromatographic characteristics of MMC stationary phase were adjusted.OTAS was used to separate the mixtures of 11 compounds with different properties at the same time,and 5 inorganic anions in the actual samples of surface water source of the Yellow River main stream were determined.2.The preparation and application of reversed phase/strong anion exchange mixed-mode chromatographic stationary phase: On the basis of the preparation of MMC stationary phase OTAS,a RP/SAX type MMC stationary phase OQAS was prepared by converted tertiary amines into quaternary amines.Compared with OTAS,OQAS has stronger retention for anions.Thus OQAS has higher chromatographic peak capacity and higher selectivity in the separation of anionic compounds.5inorganic anions,5 phenoxyacetic acid herbicides and 12 different kinds of small molecule organic compounds were separated by OQAS,respectively.3.The preparation and application of reversed phase/weak cation exchange mixed mode chromatography stationary phase: A kind of RP/WCX MMC stationary phase named as OSAMES was prepared.OSAMES stationary phase was used to separate seven small molecule organic compounds with different characteristics.Compared with commercial C18 column,the retention mechanism on the two columns was different.In addition,four kinds of β-receptor agonists were separated under the conditions of hydrophilic mode and mixed mode respectively.4.The preparation and application of zwitterionic/ reversed phase/ hydrophilic interaction liquid chromatography mixed mode chromatography stationary phase: On the basis of preparation of OTAS,a ZIC/ RP/ HILIC three mode MMC stationary named as OQASAS was prepared through the ammonolysis reaction on OTAS surface.OQASAS can provide hydrophobic interaction,strong anion exchange interaction,strong cation exchange interaction and hydrophilic interaction and was used to separate the mixture of 8 substances with different characteristics.Five inorganic anions were separated by OQASAS in a short time.OQASAS was also used to separate 4 β-receptor agonists in hydrophilic chromatographic mode.Finally,the quantitative test method for phenoxyacetic acid herbicide was established and the actual sewage samples were tested.5.The verification and quantitative calculation of the MMC retention behavior using SDT-R and one site and two sites retention models: Through the fitting of the test datum,the retention of MMC in different chromatographic mode can be described by the SDT-R first linear equation.Using one-site and two-site retention model,the effect of ion-exchange retention to the total retentin was calculated.