Thin film molecularly imprinted polymers for environmental and biological sample preparations and analysis

Shahhoseini, Fereshiteh (2022) Thin film molecularly imprinted polymers for environmental and biological sample preparations and analysis. Doctoral (PhD) thesis, Memorial University of Newfoundland.

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Abstract

Sample preparation has always been the challenging part of analysis in both environmental and biological samples. The need for trace monitoring of organic pollutants in different water matrices has initiated a lot of research to develop a sensitive sample preparation method. Furthermore, with the advancement in precision medicine facilitating healthy lives, a high throughput and simple biological sample preparation is of prime importance. Besides the challenges in sensitivity, throughput and simplicity, matrix effect is a serious problem in sample preparation techniques which adversely affect the accuracy of the results in both environmental water and biofluid analysis. Molecularly imprinted polymer (MIP) sorbents implementation in sample preparation devices can add selectivity in extraction of targeted analytes and limit the matrix effect. In this thesis, MIP sorbent were fabricated on a frosted glass and a stainless-steel substrate to produce MIP-thin film microextraction (MIP-TFME) devices for water and plasma samples analysis, respectively. Polycyclic aromatic hydrocarbons (PAHs) pollutants in different water matrices were extracted using a MIP-TFME device previously developed in Dr. Bottaro’s research group. The device size was decreased compared to previous studies to accommodate a high throughput method for analysis of sixteen regulated PAHs with detection limits ranging from 2 ng L⁻¹ to 400 ng L⁻¹ using gas chromatography with atmospheric pressure chemical ionization mass spectrometry (GC-APCI-MS). As for bioanalysis, a MIP-TFME device was developed for analysis of tricyclic antidepressants (TCAs) in plasma by optimizing different parameters affecting the MIP performance such as template: monomer ratio, monomer:crosslinker ratio and progen volume. TCAs were extracted using the optimized MIP-TFME device and analytical method from pooled human plasma and patient samples; and quantified using ultra high-performance liquid chromatography-tandem mass spectrometry. The optimized MIP-TFME device showed good selectivity over corresponding non-imprinted polymers (imprinting factors 2.36-4.36). In another bioanalysis study, the applicability of an optimized porous polymer thin film device as a micro-sampling technique for analysis of TCAs was assessed. These devices allowed for analysis of small volume (10 μL) of plasma sample using spot extraction procedure. Important factors affecting the extraction efficiency such as sample volume, solvent desorption, washing, and the time of the extraction were studied to develop and validate the analytical method. Two spiked individual plasma samples were analyzed using the validated method and the obtained data proved the acceptable accuracy (86.7% to 114%) and precision (RSD values of 0.1-10%) of this method. Further evaluation such as matrix effect, method of normalization using deuterated compound and preservation of the extracted TCAs were performed. The satisfactory results of these studies provided more confirmation of the suitability of the porous thin film device for microsampling analysis of TCAs in plasma samples.

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