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Title: Synthetic modification and characterisation of poly(styrene-co-divinylbenzene) resins and their possible application in environmental analysis
Author: Dempster, Nicola M.
Awarding Body: Liverpool John Moores University
Current Institution: Liverpool John Moores University
Date of Award: 2012
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Chromatographic micro-beads of the hypercrosslinked poly(styrene-co-divinylbenzene) (PS-OV8) chromatographic adsorbent Amberchrom CG161m, were modified by introduction of polar functional groups using Friedel-Crafts acylation and Bronsted-Lowry nitrating reactions. The Amberchrom CG161m™ microbeads were functionalised by attachment of acetyl, chloroacetyl, dichloroacetyJ, methoxyacetyl, bromoacetyl, nitro and amino groups. Introduction of polar moieties enhances the etridency of the solid phase extraction (SPE) resins by improving surface contact with aqueous samples, increasing capacity and extraction of polar compounds and facilitating greater recovery of strongly held hydrophobic contaminants due to the hydrophilic-lipophilic balance of the adsorbent surface. Fourier-transform infrared spectroscopy (FT-IR), micro-elemental analysis (CHN), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), x-ray fluorescence (XRF), scanning electron microscopy (SEM) and nitrogen adsorption analyses (BET/BJI-I/DFT) were used to characterise the physico-chemical parameters of the novel functionalised resins and confirm success of the chemical reactions. The pristine Amberchrom microbeads, chemically modified PS-DVB adsorbents and bulk commercial resins (Biotage 1ST Env+TM , 1ST C18 EC and Waters Oasis HLB) were packed into analytical columns and solute-sorbent interactions evaluated from retention parameters of interrogative analytes using HPLC. Differences in physical and chemical characteristics of the SPE packing materials were identified and their influences on solute retention parameters and capacities assessed. An objective assessment of solute retention mechanisms on funclionalised sorbents was conducted in sifica using data reduction techniques and chemometric models from HPLC evaluation of solutes based on substituted benzenes. Data reduction techniques included Genetic Factor Approximation (GFA), Principal Component Analysis (PCA) and Factor Analysis (FA), with quantitative structure retention relationships (QSRR) and stepwise multi-linear regression analysis (Stepwise-MLRA) employed for computational modelling. The chemometric elucidation of sorption and elution mechanisms provided further insight into the chromatographic system and clarified perspectives and benefits of the polar functionalised resins and their potential as SPE resins. Chloroacetylated, dichloroacetyJated and methoxyacetylated PS-OVB resins were identified as adsorbents with favourable characteristics for extraction of polar analytes. Chloroacetylated and dichloroacetylated-PS-OVB sorbents also demonstrated a chemical flexibility that could be manipulated to enable mixed-mode retention for multi-residue extraction methods
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available