Design of nanostructured material for sorbent based microextraction combined with chromatographic techniques for analysis of emerging pollutants in water

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

Development of liquid phase microextraction techniques for analysis of engineered nanoparticles and selected emerging pollutants in wastewater

Abstract: Engineered nanoparticles (ENPs) are particles between 1 and 100 nanometres in size with a surrounding interfacial layer. These engineered nanoparticles are currently classified as a new class of emerging pollutants. Industries that are responsible for the production of food, pigments and paints, textiles, pharmaceuticals, cosmetics and electronics are believed to be the source of engineered nanoparticles into the environment. The unfortunate part is that there are no regulations put in place on their limitation in the environment and living organisms may not have proper mechanisms to deal with their exposure. These engineered nanoparticles pose characteristics of being tiny and microscopic, therefore, they can easily penetrate and reside inside the cells of living organisms and in that case they are classified as potential carcinogens. Antibiotics also contributes to the class of emerging pollutants. Antibiotics are known as a type of antimicrobial substances that are active against bacteria and are the most important types of antibacterial agents for fighting bacterial infections. Antibiotic pharmaceutical drugs are widely used in the treatment and prevention of such infections. They may either kill or inhibit the growth of bacteria. Antibiotics are either excreted or disposed into the environment after use. There are various ways in which these antibiotics enter the environment, this includes run offs from water bodies, leaking septic tanks and the release of wastewater effluents, hence the release of these antibiotics into the environment does not stop. For this reason, it is very crucial to monitor the availability, presence and levels of antibiotics into the environment. Emerging pollutants are present in the environment at trace levels and bounded to complex matrices which makes it difficult to analyse them using analytical techniques. Therefore, the aim of this study was to develop sample preparation methods in order to assist the shortcomings of conventional analytical detection techniques (such as inductively coupled plasma optical emission spectrometry (ICP-OES) and high performance liquid chromatography (HPLC)) encountered during the analysis of emerging pollutants. To achieve the aim of the study, three different sample preparation techniques were investigated: supramolecular solvent based microextraction, vortex assisted dispersive liquid-liquid microextraction (VA-DLLME) and ultrasound assisted surfactant based dispersive liquid-liquid microextraction (UAS-DLLME). Firstly, a supramolecular solvent based microextraction technique was developed for the extraction, separation and preconcentration of selected fluoroquinolone antibiotics coupled...M.Sc. (Applied Chemistry

Recent Advances in Solid-Phase Extraction (SPE) Based on Molecularly Imprinted Polymers (MIPs) for Analysis of Hormones

Steroid hormones are active substances that are necessary in the normal functioning of all physiological activities in the body, such as sexual characteristics, metabolism, and mood control. They are also widely used as exogenous chemicals in medical and pharmaceutical applications as treatments and at times growth promoters in animal farming. The vast application of steroid hormones has resulted in them being found in different matrices, such as food, environmental, and biological samples. The presence of hormones in such matrices means that they can easily come into contact with humans and animals as exogenous compounds, resulting in abnormal concentrations that can lead to endocrine disruption. This makes their determination in different matrices a vital part of pollutant management and control. Although advances in analytical instruments are constant, it has been determined that these instruments still require some sample preparation steps to be able to determine the occurrence of pollutants in the complex matrices in which they occur. Advances are still being made in sample preparation to ensure easier, selective, and sensitive analysis of complex matrices. Molecularly imprinted polymers (MIPs) have been termed as advanced solid-phase (SPE) materials for the selective extraction and preconcentration of hormones in complex matrices. This review explores the preparation and application of MIPs for the determination of steroid hormones in different sample types