Development and application of new analytical methods based on chromatographic and electrophoretic separations to assess the environmental behavior of anthropogenic pollutants and their uptake in fungi and chironomids

Anthropogenic contaminants are ubiquitous in the environment. These environmental pollutants enter the environment via various entry path for example wastewater treatment plants or pesticide application in agriculture. Released into the environment some are detected in surface waters. The environmental fate of contaminants depends on their physicochemical properties and on the local conditions. Contaminants may be transformed by biotic or abiotic processes like photo-transformation or hydrolysis. Aquatic organisms are exposed to contaminants which are present in water. To analyze trace amounts of contaminants in surface waters preconcentration and cleanup techniques are required to enable their detection with sensitive methods like mass spectrometry. Especially, the analysis of ionic and ionizable compounds is challenging and these compounds come more into focus as many metabolites are more polar than the parent compounds. In this thesis, electrophoretic techniques were investigated for their ability to fractionate and preconcentrate wastewater chemicals. Two different free flow modes were applied to surface water samples and an HPLC-MS method was developed for identification and quantification of 92 chemicals relevant in wastewater in the low ng/L range. In a second approach the impact of experimental conditions on the preconcentration of ionic analytes by electrophoretic techniques was investigated. Aquatic organism are exposed to chemicals present in surface waters and in case of benthic living organisms additionally to sediment bound contaminants. Some of these chemicals are taken up by the organisms and may pose adverse effects. Incorporated chemicals might be metabolized, accumulated or excreted by the organisms. Bioaccumulation leads to higher concentrations in the organisms than in the surrounding water. Therefore, the analysis of xenobiotics in organisms is of special interest to detect compounds of concern as well as to more precisely predict the environmental behavior of compounds. In this thesis, extraction and quantification of the contaminants and their transformation products were achieved based on QuEChERS extraction and following analysis by HPLC-MS. The method was applied to different organisms from exposure experiments. For the pharmaceutical carbamazepine a quantification method was developed to analyze the internal concentration in Chironomus riparius larvae and adult midges in the low ng/g range. The method was applied to assess the transfer of the pharmaceutical from aquatic to terrestrial stages and thus the transfer to the terrestrial ecosystems. Analysis of larvae and midges from emergence studies indicated a transfer of 100 % carbamazepine body burden from larvae to midges. The developed method for analysis of the neonicotinoid thiacloprid was needed only 5 Chironomus riparius larvae and enabled quantification with a limit of detection of 12 ng/g wet weight. A third procedure was developed to analyze the fungicide propiconazole and three of its metabolites in fungi mycelium in the low ng/g range. To assess the impact of sorption to nanoparticles on the environmental fate of the chemicals, thiacloprid and propiconazole were quantified in larvae and fungi which were exposed to the pesticide in the presence of nanoparticles, which were demonstrated to sorb the pesticide. Analysis of thiacloprid residues larvae revealed equal concentrations in experiments independent from nanoparticles. Reduced transformation of propiconazole in fungi experiments was detected depending on the nanoparticle concentration in liquid culture experiments and reduced propiconazole uptake in experiments on agar plates. The analysis of different fungi species revealed strong inter species differences in and uptake and metabolism of the fungicide

Biosensors for Environmental Monitoring

Real-time and reliable detection of molecular compounds and bacteria is essential in modern environmental monitoring. For rapid analyses, biosensing devices combining high selectivity of biomolecular recognition and sensitivity of modern signal-detection technologies offer a promising platform. Biosensors allow rapid on-site detection of pollutants and provide potential for better understanding of the environmental processes, including the fate and transport of contaminants.This book, including 12 chapters from 37 authors, introduces different biosensor-based technologies applied for environmental analyses

Review of geometries and coating materials in solid phase microextraction: Opportunities, limitations, and future perspectives

The final publication is available at Elsevier via http://dx.doi.org/10.1016/j.aca.2017.05.035 © 2017. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/The development of new support and geometries of solid phase microextraction (SPME), including metal fiber assemblies, coated-tip, and thin film microextraction (TFME) (i.e. self-supported, fabric and blade supported), as well as their effects on diffusion and extraction rate of analytes were discussed in the current review. Application of main techniques widely used for preparation of a variety of coating materials of SPME, including sol-gel technique, electrochemical and electrospinning methods as well as the available commercial coatings, were presented. Advantages and limitations of each technique from several aspects, such as range of application, biocompatibility, availability in different geometrical configurations, method of preparation, incorporation of various materials to tune the coating properties, and thermal and physical stability, were also investigated. Future perspectives of each technique to improve the efficiency and stability of the coatings were also summarized. Some interesting materials including ionic liquids (ILs), metal organic frameworks (MOFs) and particle loaded coatings were briefly presented

Fundamentals, Applications, and Future Directions of Bioelectrocatalysis

Bioelectrocatalysis is an interdisciplinary research field combining bio-catalysis and electrocatalysis via the utilization of materials derived from biological systems as catalysts to catalyze the redox reactions occurring at an electrode. Bioelectrocatalysis synergistically couples the merits of both biocatalysis and electrocatalysis. The advantages of biocatalysis include high activity, high selectivity, wide substrate scope, and mild reaction conditions. The advantages of electrocatalysis include the possible utilization of renewable electricity as an electron source and high energy conversion efficiency. These properties are integrated to achieve selective biosensing, efficient energy conversion, and the production of diverse products. This review seeks to systematically and comprehensively detail the fundamentals, analyze the existing problems, summarize the development status and applications, and look toward the future development directions of bioelectrocatalysis. First, the structure, function, and modification of bioelectrocatalysts are discussed. Second, the essentials of bioelectrocatalytic systems, including electron transfer mechanisms, electrode materials, and reaction medium, are described. Third, the application of bioelectrocatalysis in the fields of biosensors, fuel cells, solar cells, catalytic mechanism studies, and bioelectrosyntheses of high-value chemicals are systematically summarized. Finally, future developments and a perspective on bioelectrocatalysis are suggested

Degradation of persistent organic pollutants (pharmaceuticals & dyes) by combined dielectric barrier electrohydraulic discharge system and photo catalysts

Philosophiae Doctor - PhDWater pollution problems have continued to increase not only in South Africa but worldwide due to human activities. The presence of organic toxins and bacteria in water sources is mostly due to population growth, industrial development and agricultural run-off. The accumulation of persistent organic pollutants (POPs) in water and wastewater sources has raised various questions on the safety of potable water used for drinking, households and other activities. Traditional mechanical, biological, physical, and chemical methods such as flocculation, coagulation, reverse osmosis, filtration, ultrafiltration, adsorption and active sludge treatment methods have failed to remove these new xenobiotic from aquatic media. This is due to the fact that instead of degrading the toxins, the methods listed above often transform organic contaminants from one form another. Also, the post treatment of by-products resulting from these methods is costly. In addition, this new generation of contaminants, often referred to as compounds of emerging concern (CECs), exist in tiny concentrations (ng) and conventional techniques have not been designed for these low levels of pollutants which consequently pass through during treatment processes and end up in the treated effluents at minute concentrations (ug/L to ng/L). However, complete remediation of chemical toxins in wastewater treatment plants has not been achieved. A better option involves the direct oxidation of the pollutants in the effluent but so far their complete mineralisation has not been achieved. Advanced oxidation processes (AOPs) have emerged in recent years as adequate techniques for the complete removal of POPs. AOPs focus more on the production of non-selective hydroxyl radicals (OH.) which have been considered as the most powerful oxidants (2.8 V) that directly or indirectly mineralise the organic pollutant into dissolved CO2, H2O and harmless end-products. However, the use of excessive chemicals, corrosion of catalyst supports, wasted UV, ozone escapes and the cost associated with AOPs often limit their application for the removal of POPs from water and wastewater treatment facilities. The principal aim of this study was to optimise a double cylindrical barrier discharge (DBD) system for the removal of low concentration persistent organic pollutants (POPs). The efficiency of the DBD system was initially confirmed by quantification of three main reactive oxygen species including ozone (O3), hydrogen peroxide (H2O2) and hydroxyl radicals (.OH) among others. These three active species were successfully detected and quantified using indigo, per titanyl sulphate and terephthallic acid (TA) spectroscopy methods, respectively. Thereafter, the DBD reactor was optimised by assessing the effect of electrophysico-chemical parameters on the removal efficiencies of two selected pollutants including orange II sodium salt dye (O.II) and sulfamethoxazole (SMX), a pharmaceutical, as model persistent organic pollutants

Pharmaceutical Particulates and Membranes for Delivery of Drugs and Bioactive Molecules

This book is a collection of papers published in the Special Issue of Pharmaceutics, entitled "Pharmaceutical Particulates and Membranes for Delivery of Drugs and Bioactive Molecules". A drug release profile is a consequential factor for nanoparticle application, directly related to drug stability and therapeutic results, as well as formulation development. Pharmaceutical particulates of different sizes and shapes (e.g., liposomes, oil-in-water emulsions, polymeric nano- and microspheres, metallic nanoparticles (NPs) such as gold, silver and iron oxide crystals, and core-shell hybrid NPs) offer many diagnostic and therapeutic applications. Membranes are also extensively utilized in many applications. They are especially beneficial to the distribution of macromolecular drugs and biopharmaceutical drugs (peptides, proteins, antibodies, oligonucleotides, plasmids, and viruses) with physicochemical and pharmacokinetic vulnerability. The delivery of drugs and bioactive molecules using particulates and membranes has gained a great deal of attention for various applications, such as the treatment of secondary infections, cancer treatment, skin regeneration, orthopaedic applications, and antimicrobial drug delivery. In addition, several production techniques have been utilized for the fabrication of particulates and membranes in the last decade, which include lyophilisation, micro-emulsion, nano-spray dryer, nano-electrospinning, slip casting and 3D printers. Therefore, pharmaceutical particulates and membranes possess excellent prospects to deliver drugs and bioactive molecules with the potential to improve new delivery strategies like sustained and controlled release

Synthesis of new pyrazolium based tunable aryl alkyl ionic liquids and their use in removal of methylene blue from aqueous solution

In this study, two new pyrazolium based tunable aryl alkyl ionic liquids, 2-ethyl-1-(4-methylphenyl)-3,5- dimethylpyrazolium tetrafluoroborate (3a) and 1-(4-methylphenyl)-2-pentyl-3,5-dimethylpyrazolium tetrafluoroborate (3b), were synthesized via three-step reaction and characterized. The removal of methylene blue (MB) from aqueous solution has been investigated using the synthesized salts as an extractant and methylene chloride as a solvent. The obtained results show that MB was extracted from aqueous solution with high extraction efficiency up to 87 % at room temperature at the natural pH of MB solution. The influence of the alkyl chain length on the properties of the salts and their extraction efficiency of MB was investigated

Properties and Applications of Graphene and Its Derivatives

Graphene is a two-dimensional, one-atom-thick material made entirely of carbon atoms, arranged in a honeycomb lattice. Because of its distinctive mechanical (e.g., high strength and flexibility) and electronic (great electrical and thermal conductivities) properties, graphene is an ideal candidate in myriad applications. Thus, it has just begun to be engineered in electronics, photonics, biomedicine, and polymer-based composites, to name a few. The broad family of graphene nanomaterials (including graphene nanoplatelets, graphene oxide, graphene quantum dots, and many more) go beyond and aim higher than mere single-layer (‘pristine’) graphene, and thus, their potential has sparked the current Special Issue. In it, 18 contributions (comprising 14 research articles and 4 reviews) have portrayed probably the most interesting lines as regards future and tangible uses of graphene derivatives. Ultimately, understanding the properties of the graphene family of nanomaterials is crucial for developing advanced applications to solve important challenges in critical areas such as energy and health