Evaluation of novel mixed-mode ion-exchange materials to address environmental analytical problems

Identifier:  TDX:3986

Handle: https://hdl.handle.net/20.500.11797/TDX3986

Authors:  Nadal Lozano, Joan Carles

Abstract:
Nowadays, there is a necessity of determining emerging organic contaminants in environmental samples owing to their widespread use and the contamination issues they cause on environment. Due to the several compounds and their low concentration in the environment, selective and sensitive analytical methods have to be developed to determine these contaminants in the environmental samples. Analytical methods involving sample preparation and determination of analytes in complex matrices are essential in modern-day analysis, being sample preparation the critical factor. Several extraction techniques can be used depending on the type of sample, being solid-phase extraction (SPE), solid-phase microextraction, and stir bar sorptive extraction (SBSE), among others recently developed, the most used for sample treatment of liquid samples. In recent years, the preparation of materials with high sorption capacity and selectivity toward target analytes has been the focus of interest in the research on sorptive extraction techniques. Therefore, this Doctoral Thesis focuses on the development and evaluation of in-house mixed-mode ion-exchange materials for sorptive extraction techniques to address environmental analytical problems. The first section focuses on the preparation of in-house hypercrosslinked mixed-mode ion-exchange materials and their evaluation by SPE to extract ionizable analytes including pharmaceuticals, artificial sweeteners and illicit drugs from environmental waters. The novelty of these studies is based on the introduction of the zwitterionic character to the sorbent which enable acidic and basic analytes to be simultaneously and selectively extracted from the sample. In the section devoted to the SBSE and capsule phase microextraction (CPME) techniques, in-house mixed-mode ion-exchange materials were synthesized to be used as coatings for the SBSE and CPME of a group of ionizable compounds. The developed methods using liquid chromatography followed by tandem mass spectrometry were validated and applied to selectively determine the studied compounds in different environmental water samples.