Synthesis of new classes of ionic liquids and their utilization in biological and pharmaceutical analysis

Ionic Liquids (ILs) are molten organic solvents comprised of unsymmetrical organic cations and inorganic/organic anions with melting points below 100 ˚C. The unique physicochemical properties of ILs including high thermal stabilities, negligible vapor pressures at room temperature, and tunable solubilities and viscosities have tremendously increased their applications in analytical chemistry. The first part of research work presented in this dissertation focuses on different synthetic strategies that are employed to tailor the physicochemical properties as well as paramagnetic susceptibilities of magnetic ionic liquids (MILs). The developed synthetic methods yielded MILs with low aqueous solubilities (0.1% w/v) and high magnetic susceptibilities. The second part of dissertation describes the self-assembly properties of different classes of ILs in aqueous solutions. The last part of dissertation focuses on the applications of ILs and polymeric ionic liquids (PILs) for analysis of pharmaceuticals and nucleic acids, respectively. MILs are a special class of ILs with paramagnetic component(s) in their molecular structure. In addition to favorable properties of ILs, MILs exhibit paramagnetic susceptibilities at room temperatures when suspended in aqueous solutions. As a result their molecular motion can be readily controlled by exposure to an external magnetic field. Owing to their structural tunability as well as paramagnetic susceptibilities, MILs demonstrate a remarkable potential to address the challenges associated with liquid liquid extraction (LLE) techniques. Imidazolium-based cations with [FeCl4-]/[FeCl3Br-] anions represents the common class of MILs. The high aqueous solubility of iron (III)-based MILs represents a serious problem for their applicability in liquid liquid microextraction techniques. Three different classes of iron-based hydrophobic MILs including monocationic, dicationic, and tricationic MILs were prepared. The incorporation of long hydrocarbon chains, benzyl groups, and perfluoroalkyl alkyl moieties as substituents within cation framework has significantly improved the hydrophobicity of resulting MILs. A series of dicationic imidazolium cations with weakly coordinating and relatively hydrophobic anions yielded MILs with low melting points and low aqueous solubilities. The paramagnetic susceptibility of MILs is controlled by varying the number of paramagnetic anions in the molecular structure. The developed MILs demonstrated structure-dependent extraction properties for analysis of DNA and polycyclic aromatic hydrocarbons (PAHs) from complex sample matrices. ILs with long hydrocarbon chains and hydrophilic cations (e.g., imidazolium and pyridinium) exhibit self-assembly properties in aqueous solutions. Similar to conventional surfactants, IL-based surfactants demonstrate concentration dependent properties in aqueous solutions including bulk phase aggregation (micelle formation) and surface adsorption. The interfacial and micellar properties of three dicationic and two tricationic IL-based surfactants in aqueous solutions were examined using fluorescence spectroscopy, conductometry, and tensiometry techniques. In addition, the effects of inorganic and organic salts and organic solvent content on the aggregation properties of IL-based surfactants was investigated. The surface adsorption as well as micellar properties of tricationic IL-based surfactants was compared against the analogous trimeric quaternary ammonium-based surfactants. The high thermal stability as well as relatively low vapor pressure at high temperatures are some interesting properties of ILs that represent them as new diluent systems in headspace gas chromatography (HS-GC) applications. Two ILs were examined as HS-GC diluents for analysis of residual solvents in pharmaceutical substances. To improve the analytical performance of the developed method, the HS-GC parameters were optimized including HS extraction time and HS incubation temperature. Owing to their favorable physicochemical properties, IL-based HS-GC method yielded low detection limits (LODs), high sensitivities, and better sample throughput compared to conventional organic solvent-based HS-GC method. Solid-phase microextraction (SPME) is a miniaturized and automated solvent-free sample preparation technique. In contrast to solid-phase extraction (SPE) and LLE methods, SPME streamlines the analytical workflow by combining sampling and sample preparation into a single step. This significantly reduces the overall analysis time. PILs represent as new class of sorbent coatings with tunable solvation properties and high thermal stabilities. The unique extraction properties of PILs were exploited for the purification of nucleic acids from complex sample matrices. Electrostatic and ion–exchange interactions between negatively charged phosphate backbone of nucleic acid and cationic framework of PIL sorbent coating are the main driving force for extraction of nucleic acids by PIL sorbent coatings. The developed PIL-based SPME method purified sufficient quantity and quality of DNA from bacterial cell lysate samples and subsequently used for downstream enzymatic amplification techniques including endpoint polymerase chain reaction (PCR) and quantitative real-time PCR. Given the success of SPME toward DNA analysis, the applicability of the PIL-based SPME was also investigated for analysis of yeast RNA samples. The PIL-based sorbent coating featuring carboxylic acid groups within IL monomer and halide-based anions extracted the highest amount of mRNA from aqueous samples compared to analogous PIL sorbent coatings. Under similar experimental conditions, the PIL-based SPME method yielded higher quantities of mRNA for real-time reverse transcription quantitative PCR (RT-qPCR) compared to phenol/chloroform LLE method. The selectivity of PIL-based SPME method toward mRNA analysis was improved by modifying the surface composition of a commercial poly acrylate (PA) sorbent coating with oligo deoxythymine (dT) that assist in specific capture of mRNA from total RNA samples. The developed oligo dT modified PA-based SPME method extracted low quantity of mRNA compared to commercial silica-based S

Extraction and Purification of DNA from Complex Biological Sample Matrices Using Solid-Phase Microextraction Coupled with Real-Time PCR

The determination of extremely small quantities of DNA from complex biological sample matrices represents a significant bottleneck in nucleic acid analysis. In this study, polymeric ionic liquid (PIL)-based solid-phase microextraction (SPME) was applied for the extraction and purification of DNA from crude bacterial cell lysate with subsequent quantification by real-time PCR (qPCR) analysis. Using an on-fiber ultraviolet initiated polymerization technique, eight different PIL sorbent coatings were generated and their DNA extraction performance evaluated using qPCR. The PIL sorbent coating featuring halide anions and carboxylic acid groups in the cationic portion exhibited superior DNA extraction capabilities when compared to the other studied PILs and a commercial polyacrylate SPME fiber. Electrostatic interactions as well as an ion-exchange mechanism were identified as the driving forces in DNA extraction by the PIL sorbents. The selectivity of the PIL sorbent coating for DNA was demonstrated in the presence of PCR inhibitors at high concentration, where a quantifiable amount of template DNA was extracted from aqueous samples containing CaCl2 and FeCl3. Furthermore, the PIL-based SPME method was successfully applied for the extraction of DNA from crude bacterial cell lysate spiked with 1 pg mL−1 template DNA without requiring the use of organic solvents or centrifugation steps. Following PIL-based SPME of DNA from a dilute cell lysate, the qPCR amplification efficiency was determined to be 100.3%, demonstrating the feasibility of the developed method to extract high purity DNA from complex sample matrices

Neuropeptidomic Components Generated by Proteomic Functions in Secretory Vesicles for Cell–Cell Communication

Diverse neuropeptides participate in cell–cell communication to coordinate neuronal and endocrine regulation of physiological processes in health and disease. Neuropeptides are short peptides ranging in length from ~3 to 40 amino acid residues that are involved in biological functions of pain, stress, obesity, hypertension, mental disorders, cancer, and numerous health conditions. The unique neuropeptide sequences define their specific biological actions. Significantly, this review article discusses how the neuropeptide field is at the crest of expanding knowledge gained from mass-spectrometry-based neuropeptidomic studies, combined with proteomic analyses for understanding the biosynthesis of neuropeptidomes. The ongoing expansion in neuropeptide diversity lies in the unbiased and global mass-spectrometry-based approaches for identification and quantitation of peptides. Current mass spectrometry technology allows definition of neuropeptide amino acid sequence structures, profiling of multiple neuropeptides in normal and disease conditions, and quantitative peptide measures in biomarker applications to monitor therapeutic drug efficacies. Complementary proteomic studies of neuropeptide secretory vesicles provide valuable insight into the protein processes utilized for neuropeptide production, storage, and secretion. Furthermore, ongoing research in developing new computational tools will facilitate advancements in mass-spectrometry-based identification of small peptides. Knowledge of the entire repertoire of neuropeptides that regulate physiological systems will provide novel insight into regulatory mechanisms in health, disease, and therapeutics

Iron-Based Imidazolium Salts as Versatile Catalysts for the Synthesis of Quinolines and 2- and 4-Allylanilines by Allylic Substitution of Alcohols

Readily available iron(III)-based imidazolium salts have proven to be very versatile catalysts for the allylic substitution reaction of alcohols with anilines, allowing the synthesis of quinolines, 2-allylanilines and 4-allylanilines just by modulating the reaction conditions. Noteworthy, the formation of quinoline derivatives proceeds by ortho-allylation of the corresponding aniline and subsequent oxidative cyclization mediated by atmospheric oxygen. The reaction using anilines as nucleophiles is selective to the C-alkylation versus the N-alkylation, under any reaction conditions studied.This work was financially supported by the University of Alicante

Synthesis of new classes of ionic liquids and their utilization in biological and pharmaceutical analysis

Ionic Liquids (ILs) are molten organic solvents comprised of unsymmetrical organic cations and inorganic/organic anions with melting points below 100 ˚C. The unique physicochemical properties of ILs including high thermal stabilities, negligible vapor pressures at room temperature, and tunable solubilities and viscosities have tremendously increased their applications in analytical chemistry. The first part of research work presented in this dissertation focuses on different synthetic strategies that are employed to tailor the physicochemical properties as well as paramagnetic susceptibilities of magnetic ionic liquids (MILs). The developed synthetic methods yielded MILs with low aqueous solubilities (0.1% w/v) and high magnetic susceptibilities. The second part of dissertation describes the self-assembly properties of different classes of ILs in aqueous solutions. The last part of dissertation focuses on the applications of ILs and polymeric ionic liquids (PILs) for analysis of pharmaceuticals and nucleic acids, respectively. MILs are a special class of ILs with paramagnetic component(s) in their molecular structure. In addition to favorable properties of ILs, MILs exhibit paramagnetic susceptibilities at room temperatures when suspended in aqueous solutions. As a result their molecular motion can be readily controlled by exposure to an external magnetic field. Owing to their structural tunability as well as paramagnetic susceptibilities, MILs demonstrate a remarkable potential to address the challenges associated with liquid liquid extraction (LLE) techniques. Imidazolium-based cations with [FeCl4-]/[FeCl3Br-] anions represents the common class of MILs. The high aqueous solubility of iron (III)-based MILs represents a serious problem for their applicability in liquid liquid microextraction techniques. Three different classes of iron-based hydrophobic MILs including monocationic, dicationic, and tricationic MILs were prepared. The incorporation of long hydrocarbon chains, benzyl groups, and perfluoroalkyl alkyl moieties as substituents within cation framework has significantly improved the hydrophobicity of resulting MILs. A series of dicationic imidazolium cations with weakly coordinating and relatively hydrophobic anions yielded MILs with low melting points and low aqueous solubilities. The paramagnetic susceptibility of MILs is controlled by varying the number of paramagnetic anions in the molecular structure. The developed MILs demonstrated structure-dependent extraction properties for analysis of DNA and polycyclic aromatic hydrocarbons (PAHs) from complex sample matrices. ILs with long hydrocarbon chains and hydrophilic cations (e.g., imidazolium and pyridinium) exhibit self-assembly properties in aqueous solutions. Similar to conventional surfactants, IL-based surfactants demonstrate concentration dependent properties in aqueous solutions including bulk phase aggregation (micelle formation) and surface adsorption. The interfacial and micellar properties of three dicationic and two tricationic IL-based surfactants in aqueous solutions were examined using fluorescence spectroscopy, conductometry, and tensiometry techniques. In addition, the effects of inorganic and organic salts and organic solvent content on the aggregation properties of IL-based surfactants was investigated. The surface adsorption as well as micellar properties of tricationic IL-based surfactants was compared against the analogous trimeric quaternary ammonium-based surfactants. The high thermal stability as well as relatively low vapor pressure at high temperatures are some interesting properties of ILs that represent them as new diluent systems in headspace gas chromatography (HS-GC) applications. Two ILs were examined as HS-GC diluents for analysis of residual solvents in pharmaceutical substances. To improve the analytical performance of the developed method, the HS-GC parameters were optimized including HS extraction time and HS incubation temperature. Owing to their favorable physicochemical properties, IL-based HS-GC method yielded low detection limits (LODs), high sensitivities, and better sample throughput compared to conventional organic solvent-based HS-GC method. Solid-phase microextraction (SPME) is a miniaturized and automated solvent-free sample preparation technique. In contrast to solid-phase extraction (SPE) and LLE methods, SPME streamlines the analytical workflow by combining sampling and sample preparation into a single step. This significantly reduces the overall analysis time. PILs represent as new class of sorbent coatings with tunable solvation properties and high thermal stabilities. The unique extraction properties of PILs were exploited for the purification of nucleic acids from complex sample matrices. Electrostatic and ion–exchange interactions between negatively charged phosphate backbone of nucleic acid and cationic framework of PIL sorbent coating are the main driving force for extraction of nucleic acids by PIL sorbent coatings. The developed PIL-based SPME method purified sufficient quantity and quality of DNA from bacterial cell lysate samples and subsequently used for downstream enzymatic amplification techniques including endpoint polymerase chain reaction (PCR) and quantitative real-time PCR. Given the success of SPME toward DNA analysis, the applicability of the PIL-based SPME was also investigated for analysis of yeast RNA samples. The PIL-based sorbent coating featuring carboxylic acid groups within IL monomer and halide-based anions extracted the highest amount of mRNA from aqueous samples compared to analogous PIL sorbent coatings. Under similar experimental conditions, the PIL-based SPME method yielded higher quantities of mRNA for real-time reverse transcription quantitative PCR (RT-qPCR) compared to phenol/chloroform LLE method. The selectivity of PIL-based SPME method toward mRNA analysis was improved by modifying the surface composition of a commercial poly acrylate (PA) sorbent coating with oligo deoxythymine (dT) that assist in specific capture of mRNA from total RNA samples. The developed oligo dT modified PA-based SPME method extracted low quantity of mRNA compared to commercial silica-based SP</p

Extraction and Purification of DNA from Complex Biological Sample Matrices Using Solid-Phase Microextraction Coupled with Real-Time PCR

The determination of extremely small quantities of DNA from complex biological sample matrices represents a significant bottleneck in nucleic acid analysis. In this study, polymeric ionic liquid (PIL)-based solid-phase microextraction (SPME) was applied for the extraction and purification of DNA from crude bacterial cell lysate with subsequent quantification by real-time PCR (qPCR) analysis. Using an on-fiber ultraviolet initiated polymerization technique, eight different PIL sorbent coatings were generated and their DNA extraction performance evaluated using qPCR. The PIL sorbent coating featuring halide anions and carboxylic acid groups in the cationic portion exhibited superior DNA extraction capabilities when compared to the other studied PILs and a commercial polyacrylate SPME fiber. Electrostatic interactions as well as an ion-exchange mechanism were identified as the driving forces in DNA extraction by the PIL sorbents. The selectivity of the PIL sorbent coating for DNA was demonstrated in the presence of PCR inhibitors at high concentration, where a quantifiable amount of template DNA was extracted from aqueous samples containing CaCl2 and FeCl3. Furthermore, the PIL-based SPME method was successfully applied for the extraction of DNA from crude bacterial cell lysate spiked with 1 pg mL−1 template DNA without requiring the use of organic solvents or centrifugation steps. Following PIL-based SPME of DNA from a dilute cell lysate, the qPCR amplification efficiency was determined to be 100.3%, demonstrating the feasibility of the developed method to extract high purity DNA from complex sample matrices.This article is published as Nacham, O.; Clark, K. D.; Anderson, J. L. "Extraction and Purification of DNA from Complex Biological Sample Matrices using Solid-Phase Microextraction Coupled with Real-Time PCR" Analytical Chemistry, 2016, 88, 7813-7820. DOI:10.1021/acs.analchem.6b01861. Posted with permission.</p

Air Quality Index Prediction

Falling back past few years rapid progress in Air pollution has become a life-threatening concern in many nations throughout the world due to human activity, industrialisation, and urbanisation.. As a result of these activities, sulphur oxides, carbon dioxide (CO2), nitrogen oxides, carbon monoxide (CO), chlorofluorocarbons (CFC), lead, mercury, and other pollutants be emitted into atmosphere. Simultaneously, estimating quality of air is a tough undertaking because of evolution, variability, also unreasonable unpredictability over pollution and particle region and time. In this project we compare the two Algorithms of machine learning in predicting Index of Air Quality and its predominant. Support vector machine (SVM) exists as prominent machine learning method beneficial to forecasting pollutant plus particle levels and predicting the air quality index (AQI), and Random Forest Regression is another. We'll be working with data from India's Open Government Data Platform. This website displays Air Quality Index readings from around India, including Sulphur Dioxide (SO2), Nitrogen Dioxide (NO2), and Particulate Matter (PM) are examples of contaminants (PM10 and PM2.5), Carbon Monoxide (CO), and others. The output of the project is the predict of Air Quality index using two different algorithms and the comparison of models using various error metrics

Synthetic Strategies for Tailoring the Physicochemical and Magnetic Properties of Hydrophobic Magnetic Ionic Liquids

Magnetic ionic liquids (MILs) are a subclass of ionic liquids (ILs) containing paramagnetic components and are readily manipulated by an external magnetic field. Due to their hydrophilic nature, very few applications of MILs in aqueous systems have been reported. In this study, three general classes of hydrophobic MILs including monocationic, symmetrical/unsymmetrical dicationic, and symmetrical/unsymmetrical tricationic MILs were synthesized and characterized. By tuning the structure of the MIL, various physicochemical properties including water solubility, magnetic susceptibility, and melting point were regulated. MILs synthesized with the benzimidazolium cation were shown to exhibit lower water solubility (0.1% (w/v)) when compared to those containing imidazolium cations (0.25% (w/v)). By incorporating asymmetry into the cationic component of the MIL, the melting point of dicationic MILs was lowered while the effective magnetic moment (μ_eff) and hydrophobicity remained unchanged. Tricationic MILs paired with three [FeCl₃Br^–] anions exhibited an μ_eff as high as 11.76 Bohr magnetons (μ_B), the highest ever reported for MILs. The synthetic strategies employed in this study facilitate the generation of hydrophobic MILs that show great promise for liquid–liquid extraction and catalytic studies where the MIL can be easily removed or in microfluidic applications where the MIL microdroplet can be manipulated by an external field