Title:
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Synthetic modification and characterisation of
poly(styrene-co-divinylbenzene) resins and
their possible application in environmental analysis
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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
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