Abstract
Emerging pollutants (EPs) are defined as synthetic or naturally occurring chemicals that are not commonly monitored and regulated in the environment. These pollutants have a potential to enter the environment and cause known or suspected adverse ecological and human health effects. In some cases, the release of emerging pollutants to the environment has occurred for a long time but may not have been recognized until new detection methods were developed. Anthropogenic activities such as agriculture practices, industrial discharges, and other human activities play an important role in the introduction of emerging pollutants in environment. The emerging pollutants classification includes pharmaceuticals, personal care production (PCPs), pesticides, UV-filters, engineered nanoparticles and surfactants, amongst others. The monitoring of emerging pollutants in the environment is challenging because they are released into the environment on daily basis. These pollutants are present in trace concentrations and embedded into complex matrices of the environment, and some are found at trace levels. Therefore, direct analysis of emerging pollutants using analytical techniques is difficult. Therefore, the aim of this study was to develop sample preparation methods for extraction, clean-up and enrichment of analytes prior to analytical detection using liquid chromatography coupled with diode array detector and mass spectrometry (HPLC-DAD and LC-MS). To achieve objectives of the study, various porous nanoadsorbents were synthesized and explored for solid phase extraction of different neonicotinoid insecticides, steroid hormones and per- and polyfluoroalkyl substances (PFASs) in surface water samples. These materials included magnetic porphyrin-based porous organic polymer (MP-POP), ZIF67@MPPOP, o-hydroxyazobenzene porous organic polymer (HAzo-POP) and metal organic frameworks (UIO-66 (Zr) and Fe3O4@MIL-101 (Cr)). The adsorbents were characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy, Brunauer–Emmett–Teller (BET) surface area. Parameter affecting the developed sample preparation methods were optimised using design of experiment tools such as fractional factorial design and response surface methodology (RSM) based on Box Behnken design (BBD) and central composite design (CCD). The successive paragraphs summarise the findings for the application of each adsorbent. Firstly, MP-POP nanocomposite was applied in magnetic solid phase microextraction (MSPME) neonicotinoid insecticides in surface water. The method offered relatively, low limits of detection (LOD) and quantification (LOQ) ranging from 1.3-3.2 ng L-1 and 4.3 -11 ng L-1, as well as wide linearity (up to 600 μg L-1)...
Ph.D. (Chemistry)