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Articles 1 - 30 of 32
Full-Text Articles in Physical Sciences and Mathematics
Trends In Biomedical Analysis Of Red Blood Cells – Raman Spectroscopy Against Other Spectroscopic, Microscopic And Classical Techniques, Jakub Dybas, Fatih Celal Alcicek, Aleksandra Wajda, Magdalena Kaczmarska, Anna Zimna, Katarzyna Bulat, Aneta Blat, Tetiana Stepanenko, Tasnim Mohaissen, Ewa Szczesny-Malysiak, David Perez-Guaita, Bayden R. Wood, Katarzyna Maria Marzec
Trends In Biomedical Analysis Of Red Blood Cells – Raman Spectroscopy Against Other Spectroscopic, Microscopic And Classical Techniques, Jakub Dybas, Fatih Celal Alcicek, Aleksandra Wajda, Magdalena Kaczmarska, Anna Zimna, Katarzyna Bulat, Aneta Blat, Tetiana Stepanenko, Tasnim Mohaissen, Ewa Szczesny-Malysiak, David Perez-Guaita, Bayden R. Wood, Katarzyna Maria Marzec
Articles
Application of modern and innovative spectroscopic and microscopic approaches to biomedical analysis opens new horizons and sheds new light on many unexplored scientific territories. In this review, we critically summarize up-to-date Raman-based methodologies for red blood cells (RBCs) analysis used in biology and medicine, and compare them with both classical, as well as other spectroscopic and microscopic approaches. The main emphasis is placed on the advantages, disadvantages and capabilities of each technique for detection of RBC deteriorations and RBC-related diseases. Although currently used classical techniques of medical analysts serve as a gold standard for clinicians in diagnosis of erythropathies, they …
Immobilized-Enzyme Reactors Integrated Into Analytical Platforms: Recent Advances And Challenges, Bert Wouters Dr, Sinead Currivan, Noor Abdulhussain, T. Hankemeier, Peter J. Schoenmakers
Immobilized-Enzyme Reactors Integrated Into Analytical Platforms: Recent Advances And Challenges, Bert Wouters Dr, Sinead Currivan, Noor Abdulhussain, T. Hankemeier, Peter J. Schoenmakers
Articles
Immobilized-enzyme reactors (IMERs) are flow-through devices containing enzymes that are physically confined or localized with retention of their catalytic activities. IMERs can be used repeatedly and continuously and have been applied for (bio)polymer degradation, proteomics, biomarker discovery, inhibitor screening, and detection. Online integration of IMERs with analytical instrumentation, such as high-performance liquid chromatography (HPLC) systems, reduces the time needed for multi-step workflows, reduces the need for sample handling, and enables automation. However, online integration can also be challenging, as reaching its full potential requires complex instrumental setups and experienced users. This review aims to provide an assessment of recent advances …
Fabrication Of Polymer Monoliths Within The Confines Of Non-Transparent 3d-Printed Polymer Housings, Noor Abdulhussain, Suhas H. Nawada, Sinéad Currivan, Marta Passamonti, Peter J. Schoenmakers
Fabrication Of Polymer Monoliths Within The Confines Of Non-Transparent 3d-Printed Polymer Housings, Noor Abdulhussain, Suhas H. Nawada, Sinéad Currivan, Marta Passamonti, Peter J. Schoenmakers
Articles
In the last decade, 3D-printing has emerged as a promising enabling technology in the field of analytical chemistry. Fused-deposition modelling (FDM) is a popular, low-cost and widely accessible technique. In this study, RPLC separations are achieved by in-situ fabrication of porous polymer monoliths, directly within the 3D-printed channels. Thermal polymerization was employed for the fabrication of monolithic columns in optically non-transparent column housings, 3D-printed using two different polypropylene materials. Both acrylate-based and polystyrene-based monoliths were created. Two approaches were used for monolith fabrication, viz. (i) in standard polypropylene (PP) a two-step process was developed, with a radical initiated wall-modification step …
Structural Annotation Of Electro- And Photochemically Generated Transformation Products Of Moxidectin Using High-Resolution Mass Spectrometry, Lisa Kotthoff, Sarah-Louise O'Callaghan, Jan Lisec, Tanja Schwerdtle, Matthias Koch
Structural Annotation Of Electro- And Photochemically Generated Transformation Products Of Moxidectin Using High-Resolution Mass Spectrometry, Lisa Kotthoff, Sarah-Louise O'Callaghan, Jan Lisec, Tanja Schwerdtle, Matthias Koch
Articles
Moxidectin (MOX) is a widely used anthelmintic drug for the treatment of internal and external parasites in food-producing and companion animals. Transformation products (TPs) of MOX, formed through metabolic degradation or acid hydrolysis, may pose a potential environmental risk, but only few were identified so far. In this study, we therefore systematically characterized electro- and photochemically generated MOX TPs using high-resolution mass spectrometry (HRMS). Oxidative electrochemical (EC) TPs were generated in an electrochemical reactor and photochemical (PC) TPs by irradiation with UV-C light. Subsequent HRMS measurements were performed to identify accurate masses and deduce occurring modification reactions of derived TPs …
An Ammonia Sensor Using An Unadorned Bromocresol Layer, John Cassidy, Caoimhe Ní Néill, Merve Akdağ, Tony Betts
An Ammonia Sensor Using An Unadorned Bromocresol Layer, John Cassidy, Caoimhe Ní Néill, Merve Akdağ, Tony Betts
Articles
Bromocresol Purple,(BCP) cast onto an acetate sheet, was used to sense ammonia. This simple layer responded reversibly to a low concentration ( 15 ppm) of ammonia in the presence of water vapour. The BCP solution was spincoated on an acetate sheet from a solution in dichloromethane. This layer was exposed to nitrogen and NH3/H2O vapour in quick succession. The colour change occurred from yellow to purple rapidly in the solid state. The λmax for the neutral ( acid) form of the BCP was found to be 435 nm and the λmax for the dianion ( base form) of the BCP …
Investigation Of Coastal Sea-Fog Formation Using The Wibs (Wide Band Integrated Bioaerosol Sensor) Technique, Shane M. Daly, David O'Connor, David A. Healy, Stig Hellebust, Jovanna Arndt, Eoinj. Mcgillicuddy, Patrick Feeney, Michael Quirke, John C. Wenger, John R. Sodeau
Investigation Of Coastal Sea-Fog Formation Using The Wibs (Wide Band Integrated Bioaerosol Sensor) Technique, Shane M. Daly, David O'Connor, David A. Healy, Stig Hellebust, Jovanna Arndt, Eoinj. Mcgillicuddy, Patrick Feeney, Michael Quirke, John C. Wenger, John R. Sodeau
Articles
Abstract. A wideband integrated bioaerosol sensor (WIBS4) was deployed in Haulbowline Island, Cork Harbour, to detect fluorescence particles in real time during July and September 2011. A scanning mobility particle sizer (SMPS) was also installed providing sizing analysis of the particles over the 10–450nm range. During the campaign, multiple fog formation events occurred; they coincided with dramatic increases in the recorded fluorescent particle counts. The WIBS sizing and fluorescence intensity profiles indicated that the origin of the signals was potentially non-biological in nature (i.e. PBAPs, primary biological aerosol particles). Furthermore, the data did not support the presence of known fluorescing …
Fluorescence Quenching-Based Mechanism For Determination Of Hypochlorite By Coumarin-Derived Sensors, Karolina Starzak, Arkadiusz Matwijczuk, Bernadette Creaven, Alicja Matwijczuk, Sławomir Wybraniec, Dariusz Karcz
Fluorescence Quenching-Based Mechanism For Determination Of Hypochlorite By Coumarin-Derived Sensors, Karolina Starzak, Arkadiusz Matwijczuk, Bernadette Creaven, Alicja Matwijczuk, Sławomir Wybraniec, Dariusz Karcz
Articles
A fluorescence quenching-based mechanism for the determination of hypochlorite was proposed based on spectroscopic and chromatographic studies on the hypochlorite-sensing potency of three structurally similar and highly fluorescent coumarins. The mode of action was found to rely upon a chlorination of the coumarin-based probes resulting from their reaction with sodium hypochlorite. Importantly, the formation of chlorinated derivatives was accompanied by a linear decrease in the fluorescence intensities of the probes tested. The results obtained suggest the applicability of a coumarin-dependent hypochlorite recognition mechanism for the detection of, as well as for quantitative determination of, hypochlorite species in vitro.
Spheroid-3d And Monolayer-2d Intestinal Electrochemical Biosensor For Toxicity/Viability Testing: Applications In Drug Screening, Food Safety, And Environmental Pollutant Analysis, Evangelia Flampouri, Shahzad Imar, Kieran O'Connell, Baljit Singh
Spheroid-3d And Monolayer-2d Intestinal Electrochemical Biosensor For Toxicity/Viability Testing: Applications In Drug Screening, Food Safety, And Environmental Pollutant Analysis, Evangelia Flampouri, Shahzad Imar, Kieran O'Connell, Baljit Singh
Articles
The rise of three-dimensional cell culture systems that provide in vivo-like environments for pharmaco-toxicological models has prompted the need for simple and robust viability assays suitable for complex cell architectural structures. This study addresses that challenge with the development of an in vitro enzyme based electrochemical sensor for viability/cytotoxicity assessment of two-dimensional (2D) monolayer and three-dimensional (3D) spheroid culture formats. The biosensor measures the cell viability/toxicity via electrochemical monitoring of the enzymatic activity of nonspecific esterases of viable cells, through the hydrolysis of 1-naphthyl acetate to 1-naphthol. The proposed sensor demonstrated strong correlation (r = 0.979) with viable …
Rapid Analysis Of Magnesium In Infant Formula Powder Using Laser-Induced Breakdown Spectroscopy, Maria Markiewicz-Keszycka, Ming Zhao, Xavier Cama-Moncunill, Toufic El Arnaout, Dana Becker, Colm O'Donnell, P. J. Cullen, Carl Sullivan, Maria Piedad Casado-Gavalda
Rapid Analysis Of Magnesium In Infant Formula Powder Using Laser-Induced Breakdown Spectroscopy, Maria Markiewicz-Keszycka, Ming Zhao, Xavier Cama-Moncunill, Toufic El Arnaout, Dana Becker, Colm O'Donnell, P. J. Cullen, Carl Sullivan, Maria Piedad Casado-Gavalda
Articles
Laser-induced breakdown spectroscopy (LIBS) was investigated to determine magnesium (Mg) content in infant formula powder. To predict Mg content in the range established by the Codex Alimentarius, a partial least squares regression (PLSR) model was developed using a calibration data set (n = 30) based on full cross-validation and validated using an independent validation data set (n = 21). The prediction model performance was evaluated using the regression coefficients of determination (Rcv2 = 0.94 and Rp2 = 0.85) with the root mean square errors on cross-validation and prediction (RMSECV = 60 mg kg−1 and RMSEP = 80 mg kg−1). The …
Confocal Raman Spectroscopic Imaging For In Vitro Monitoring Of Active Ingredient Penetration And Distribution In Reconstructed Human Epidermis Model, Lynda Miloudi, Franck Bonnier, Ali Tfayli, Florent Yvergnaux, Hugh Byrne, Igor Chourpa, Emilie Munnier
Confocal Raman Spectroscopic Imaging For In Vitro Monitoring Of Active Ingredient Penetration And Distribution In Reconstructed Human Epidermis Model, Lynda Miloudi, Franck Bonnier, Ali Tfayli, Florent Yvergnaux, Hugh Byrne, Igor Chourpa, Emilie Munnier
Articles
Topically applied Active Cosmetic Ingredients (ACI) or Active Pharmaceutical Ingredients (API) efficacy is directly related to their efficiency of penetration in the skin. In vitro Reconstructed Human Epidermis (RHE) surrogate models offer in vivo like skin samples for transdermal studies. Using Delipidol®, an ACI currently used in the cosmetics industry, the capabilities to deliver accurate distribution maps and penetration profiles of this molecule by means of Confocal Raman spectroscopic Imaging have been demonstrated. Using a NCLS (Non negative constrained least squares) approach, contribution of specific molecules can be estimated at each point of spectral maps in order to deliver semi-quantitative …
Photocatalytic Properties Of G-C3n4–Tio2 Heterojunctions Under Uv And Visible Light Conditions, Rachel Fagan, Declan Mccormack, Steven J. Hinder, Suresh Pillai
Photocatalytic Properties Of G-C3n4–Tio2 Heterojunctions Under Uv And Visible Light Conditions, Rachel Fagan, Declan Mccormack, Steven J. Hinder, Suresh Pillai
Articles
Graphitic carbon nitride (g-C3N4) and titanium dioxide (TiO2) were chosen as a model system to investigate photocatalytic abilities of heterojunction system under UV and visible light conditions. The use of g-C3N4 has been shown to be effective in the reduction in recombination through the interaction between the two interfaces of TiO2 andg-C3N4. A simple method of preparing g-C3N4 through the pyrolysis of melamine was employed, which was then added to undoped TiO2 material to form the g-C3N4–TiO2 system. These materials were then fully characterized by X-ray diffraction (XRD), Brunauer Emmett Teller (BET), and various spectroscopic techniques including Raman, X-ray photoelectron …
An Effective Method For The Preparation Of High Temperature Stable Anatase Tio2 Photocatalysts, Rachel Fagan, Declan Mccormack, Suresh Pillai, Damian Synnott
An Effective Method For The Preparation Of High Temperature Stable Anatase Tio2 Photocatalysts, Rachel Fagan, Declan Mccormack, Suresh Pillai, Damian Synnott
Articles
An efficient, rapid and straightforward method for the preparation of nitrogen and fluorine (N, F) codoped high temperature stable anatase using a microwave pre-treatment is reported. Using a single source, ammonium fluoride (NH4F) for both nitrogen and fluorine, effective doping of the precursor titanium isopropoxide (TTIP) was possible. These samples were characterised for their structural and optical properties using X-ray diffraction (XRD), Fourier transform IR (FTIR), Raman spectroscopy and UV-vis spectroscopy. In terms of the anatase to rutile transition enhancement using a novel microwave assisted technique, the sample prepared in a composition of 1:8 TiO2: NH …
Improved High Temperature Stability Of Anatase Tio2 Photocatalysts By N, F, P Co-Doping, Rachel Fagan, Declan Mccormack, Steven Hinder, Suresh Pillai
Improved High Temperature Stability Of Anatase Tio2 Photocatalysts By N, F, P Co-Doping, Rachel Fagan, Declan Mccormack, Steven Hinder, Suresh Pillai
Articles
Among the three commonly occurring phases (anatase, rutile, and brookite) of TiO2, the anatase form is reported to be the best photocatalyst due to the improved charge-carrier mobility and the greater number of surface hydroxyl groups. The anatase to rutile transition in titania photocatalysts usually occurs at a temperature between 500 °C to 700 °C. Development of a high temperature stable (above 1000 °C) anatase phase is important for various environmental applications (e.g. self-cleaning ceramic tiles, anti-microbial sanitary wares, etc.). In this study, the use of ammonium hexafluorophosphate as a single source dopant (method A) and urea, trifluoroacetic acid and …
Bis(Spirolactam) 1,3-Double-Armed Calix[4]Arene Compounds And Their Application As Extractants For The Determination Of Heavy Metal Ions, Fintan Kelleher, Mary Deasy, James Ward, Li Li, Fiona Regan
Bis(Spirolactam) 1,3-Double-Armed Calix[4]Arene Compounds And Their Application As Extractants For The Determination Of Heavy Metal Ions, Fintan Kelleher, Mary Deasy, James Ward, Li Li, Fiona Regan
Articles
A number of double-armed calix[4]arene compounds, with proline-derived spirolactam ligating groups on the lower rim, have been synthesised and investigated as extractants of toxic heavy metal ions from aqueous solution. Pedersen’s extraction technique was employed to determine the capability of these new 1,3-distal derived calix[4]arene spiroalactams to extract selected heavy metal ions (e.g. Pb2+, Cd2+, Zn2+, Cu2+, Ni2+, Co2+) from an aqueous phase into an organic phase. The percentage extraction was calculated using UV-vis spectroscopy. All of the compounds synthesised demonstrated good selectivity for the heavy metals selected …
Reference Material Development For Paralytic Shellfish Poisoning Toxins And Associated Analytical Applications, Stephen Burrell
Reference Material Development For Paralytic Shellfish Poisoning Toxins And Associated Analytical Applications, Stephen Burrell
Doctoral
Food poisoning incidences relating to marine biotoxins are a global phenomenon and have the potential to severely impact the aquaculture industry. As a result, and as a legislative requirement in the European Union (EU), many countries have implemented monitoring programmes for these compounds but their success relies on the availability of certain quality assurance tools, two of which are reference materials (RMs) and proficiency testing. The limited amounts of RMs, in particular matrix certified reference materials (CRMs) for paralytic shellfish poisoning (PSP) toxins has been a limiting factor in the implementation of alternatives to the mouse bioassay for routine monitoring …
The Bench Synthesis Of Silver Nanostructures Of Variable Size And An Introductory Analysis Of Their Optical Properties, Aoife Power, Tony Betts, John Cassidy
The Bench Synthesis Of Silver Nanostructures Of Variable Size And An Introductory Analysis Of Their Optical Properties, Aoife Power, Tony Betts, John Cassidy
Articles
A laboratory practical was designed for use by both undergraduate and second level students to demonstrate the synthesis and characterisation of tuneable silver colloids. It clearly illustrates the novel optical properties of silver nanoparticles compared to the bulk metal. The synthesis is both rapid and repeatable, and can be conducted on the laboratory bench at room temperature.
Preparation And Rapid Analysis Of Antibacterial Silver, Copper And Zinc Doped Sol–Gel Surfaces, Brendan Duffy, Swarna Jaiswal, Patrick Mchale
Preparation And Rapid Analysis Of Antibacterial Silver, Copper And Zinc Doped Sol–Gel Surfaces, Brendan Duffy, Swarna Jaiswal, Patrick Mchale
Articles
The colonisation of clinical and industrial surfaces with microorganisms, including antibiotic-resistant strains, has promoted increased research into the development of effective antibacterial and antifouling coatings. This study describes the preparation of metal nitrate (Ag, Cu, Zn) doped methyltriethoxysilane (MTEOS) coatings and the rapid assessment of their antibacterial activity using polyproylene microtitre plates. Microtitre plate wells were coated with different volumes of liquid sol–gel and cured under various conditions. Curing parameters were analysed by thermogravimetric analysis (TGA) and visual examination. The optimum curing conditions were determined to be 50–70C using a volume of 200ul. The coated wells were challenged with Gram-positive …
Preparation And Characterization Of A Composite Of Gold Nanoparticles And Single-Walled Carbon Nanotubes And Its Potential For Heterogeneous Catalysis, Anne Shanahan, James Sullivan, Mary Mcnamara, Hugh Byrne
Preparation And Characterization Of A Composite Of Gold Nanoparticles And Single-Walled Carbon Nanotubes And Its Potential For Heterogeneous Catalysis, Anne Shanahan, James Sullivan, Mary Mcnamara, Hugh Byrne
Articles
A single-walled carbon nanotube-supported gold nanoparticle composite was prepared and characterized by X-ray diffraction, scanning transmission electron microscopy/scanning electron microscopy/transmission electron microscopy, energy-dispersive X-ray analysis, atomic absorption spectroscopy, nitrogen adsorption, Raman spectroscopy, and ultraviolet-visible spectroscopy. The Au particles were found to be crystalline, with a well-defined and narrow particle-size distribution, centered around 7 nm. The activity and selectivity of the composite for solventless aerobic oxidation of a secondary alcohol were examined, and a conversion efficiency of 95% was obtained.
Non Aggregated Colloidal Silver Nanoparticles For Surface Enhanced Resonance Raman Spectroscopy, Aoife Power, John Cassidy, Tony Betts
Non Aggregated Colloidal Silver Nanoparticles For Surface Enhanced Resonance Raman Spectroscopy, Aoife Power, John Cassidy, Tony Betts
Articles
Silver nanoparticles with a tuneable l max were produced as colloids by heterogeneous nucleation. The synthesis process is both fast and repeatable, producing stable PVA capped nanoparticles. The colloid’s effectiveness in the SERRS system was investigated using Rhodamine 6G, R6G, Crystal Violet, CV, and Malachite Green, MG, as probe molecules. A clear sensing trend was observed, where the Raman signal emitted was significantly enhanced by the addition of silver nanoparticles. A build up of signal intensity is observed until an optimum ratio is achieved, followed by a decline in signal intensity as the concentration of nanoparticles is further increased. The …
Development And Validation Of A Rapid Multi-Class Method For The Confirmation Of Fourteen Prohibited Medicinal Additives In Pig And Poultry Compound Feed By Liquid Chromatography Tandem Mass Spectrometry, Mark Cronly, Patrice Behan, Barry Foley, Liam Regan, Marella Gallagher, Sean Earley, Paula Shearan, Edward Malone
Development And Validation Of A Rapid Multi-Class Method For The Confirmation Of Fourteen Prohibited Medicinal Additives In Pig And Poultry Compound Feed By Liquid Chromatography Tandem Mass Spectrometry, Mark Cronly, Patrice Behan, Barry Foley, Liam Regan, Marella Gallagher, Sean Earley, Paula Shearan, Edward Malone
Articles
A confirmatory method has been developed to allow for the analysis of fourteen prohibited medicinal additives in pig and poultry compound feed. These compounds are prohibited for use as feed additives although some are still authorised for use in medicated feed. Feed samples are extracted by acetonitrile with addition of sodium sulphate. The extracts undergo a hexane wash to aid with sample purification. The extracts are then evaporated to dryness and reconstituted in initial mobile phase. The samples undergo an ultracentrifugation step prior to injection onto the LC-MS/MS system and are analysed in a run time of 26 minutes. The …
Rapid Multi-Class Multi-Residue Method For The Confirmation Of Chloramphenicol And Eleven Nitroimidazoles In Milk And Honey By Liquid Chromatography Tandem Mass Spectrometry, Mark Cronly, Patrice Behan, Barry Foley, Liam Regan, Sheila Martin, Michael Doyle, Edward Malone
Rapid Multi-Class Multi-Residue Method For The Confirmation Of Chloramphenicol And Eleven Nitroimidazoles In Milk And Honey By Liquid Chromatography Tandem Mass Spectrometry, Mark Cronly, Patrice Behan, Barry Foley, Liam Regan, Sheila Martin, Michael Doyle, Edward Malone
Articles
A confirmatory method has been developed to allow for the analysis of eleven nitroimidazoles and also chloramphenicol in milk and honey samples. These compounds are classified as A6 compounds in annex IV of council regulation 2377/90 and therefore prohibited for the use in animal husbandry. Milk samples are extracted by acetonitrile with addition of NaCl, while honey samples are first dissolved in water before a similar extraction. Honey extracts undergo a hexane wash to remove impurities. Both milk and honey extracts are evaporated to dryness and reconstituted in initial mobile phase. These are then injected onto an LC-MS/MS system and …
Silver Nanoparticle Polymer Composite Based Humidity Sensor, Aoife Power, Tony Betts, John Cassidy
Silver Nanoparticle Polymer Composite Based Humidity Sensor, Aoife Power, Tony Betts, John Cassidy
Articles
Silver nanoparticles were synthesised by a chemical reduction process in order to produce an aqueous colloidal dispersion. The resulting colloids were then characterised by a combination of UV-Vis spectroscopy, dynamic light scattering, X-ray diffraction and transmission electron microscopy and the nanoparticles were found to have an average diameter of 20–22 nm. The Ag/polymer nanocomposites were then applied to platinum interdigital electrodes as sensor coatings and the capability of the resulting sensor as a humidity detector investigated. With the application of 1 V, a current developed which was found to be directly proportional to humidity levels. The sensor gives a reversible, …
Improved High-Temperature Stability And Sun-Light-Driven Photocatalytic Activity Of Sulfur-Doped Anatase Tio2, Suresh Pillai, Declan Mccormack, Pradeepan Periyat, John Colreavy, Steve Hinder
Improved High-Temperature Stability And Sun-Light-Driven Photocatalytic Activity Of Sulfur-Doped Anatase Tio2, Suresh Pillai, Declan Mccormack, Pradeepan Periyat, John Colreavy, Steve Hinder
Articles
No abstract provided.
Evaluation Of A Naive Model For Square Wave Voltammetry At A Microelectrode, Patrick Enright, John Cassidy, Tony Betts
Evaluation Of A Naive Model For Square Wave Voltammetry At A Microelectrode, Patrick Enright, John Cassidy, Tony Betts
Articles
A square wave voltammetric waveform ( SWV) was applied to an inlaid microdisk electrode in a solution of K4[Fe(CN)6]. A simple model relying on the assumption of steady state current throughout the scan was used to model the current potential behaviour. However, experimental peak current magnitudes were between 30% and 50% greater than those predicted by the model. The model predicts an increase of peak current and peak width at half height with pulse height Esw and no effect of the parameters frequency, f and step height, ΔEs. Experimental peak current magnitudes and peak current magnitudes predicted by the model …
An Experiment Using A Simple Photoassisted Fuel Cell Designed To Remediate Simulated Wastewater, John Cassidy, Faisa Touati, Kevin Mcguigan
An Experiment Using A Simple Photoassisted Fuel Cell Designed To Remediate Simulated Wastewater, John Cassidy, Faisa Touati, Kevin Mcguigan
Articles
Work in photochemistry work peaked in the 1980’s where there was the prospect of using sunlight shining on suspensions of titanium dioxide in order to catalytically cleave water into hydrogen and oxygen [1-5]. In this way a clean and efficient method of producing hydrogen as a fuel was envisaged. However, there was a requirement to use a rather high energy light to achieve the splitting and it was not as efficient with visible light[5]. Doped TiO2 layers have been used in a three electrode system for formic acid degradation[6]. In this work, the system uses an electrode coated with TiO2 …
Improved Nitrate Sensing Using Ion Selective Electrodes Based On Urea–Calixarene Ionophores, Benjamin Schazmann, Dermot Diamond
Improved Nitrate Sensing Using Ion Selective Electrodes Based On Urea–Calixarene Ionophores, Benjamin Schazmann, Dermot Diamond
Articles
Urea–calix[4]arenes 1 and 2 were synthesised and incorporated into ISE membranes for assessment as sensors for inorganic anions in water. 1 revealed a strong response to all anions following the Hofmeister selectivity order. For ISEs of 2, the response to a portion of the anion series was suppressed, increasing the margin of selectivity of nitrate over chloride, a common interferant of nitrate in fresh and marine water samples. The performance of ISEs containing 2 was compared to commercially available alkylammonium nitrate ion-exchange salts used for nitrate sensing. Our ISEs performed favourably in terms of sensitivity, linear range and LOD performing …
A Chloride Selective Calix[4]Arene Optical Sensor Combining Urea Functionality With Pyrene Excimer Transduction, Benjamin Schazmann, Dermot Diamond
A Chloride Selective Calix[4]Arene Optical Sensor Combining Urea Functionality With Pyrene Excimer Transduction, Benjamin Schazmann, Dermot Diamond
Articles
A neutral 2-site chloride selective compound has been developed (3), based on a 1,3- alternate tetrasubstituted calix[4]arene providing a preorganised supramolecular scaffold. The resultant supramolecular cavity is amongst the first to combine urea functional groups bridged with single methylene spacers to pyrene moieties. It combines a naturally and synthetically proven H-bonding system with the elegant ratiometric fluorescent signalling properties of an intramolecular pyrene excimer system, triggered by conformational changes upon anion coordination. The excimer emission of 3 is quenched, with a simultaneous rise in the monomer emission solely by the chloride anion amongst a wide variety of anions tested. 3 …
Development Of A Calix[4]Arene Sensor For Soft Metals Based On Nitrile Functionality, Benjamin Schazmann, Dermot Diamond
Development Of A Calix[4]Arene Sensor For Soft Metals Based On Nitrile Functionality, Benjamin Schazmann, Dermot Diamond
Articles
The current work is amongst the first to examine the potential usefulness of the nitrile functional group in potentiometric analytical sensors for soft metals. Nitrile functionality has hereby been incorporated into a calix[4]arene skeleton to give a series of new cation selective hosts. The analytical sensing behaviour of these hosts was examined by Ion Selective Electrode (ISE) based potentiometry. In all cases a preference for soft metals was observed, explained primarily in terms of soft–soft compatibility between calix[4]arene nitrile hosts and metal guests in combination with a classical ‘lock and key’ best fit mechanism. Hosts 2, 3 and 4 showed …
Identification And Recovery Of An Asymmetric Calix[4]Arene Tetranitrile Derivative Using Liquid Chromatography And Mass Spectrometry, Benjamin Schazmann, Dermot Diamond
Identification And Recovery Of An Asymmetric Calix[4]Arene Tetranitrile Derivative Using Liquid Chromatography And Mass Spectrometry, Benjamin Schazmann, Dermot Diamond
Articles
A simple analytical LC-MS (Liquid Chromatography Mass Spectrometry) method and associated instrumentation has been adapted for use by the organic chemist to yield mg quantities of target compound from a reaction mixture. Calix[4]arene 3 was identified as representing 51% of total peak area of a reaction mixture containing no less than 10 components, using LC-MS. This peak corresponded to a mass of 878.8, equivalent to a complex of 3 and an ammonium cation. Molecular models further rationalise this observation by showing that the asymmetric binding cavity of 3 is suitable for binding tetrahedral guests like the ammonium ion. By scaling …
Simulation Of Dynamic Electrochemical Processes, John Cassidy
Simulation Of Dynamic Electrochemical Processes, John Cassidy
Articles
This work is designed to introduce electrochemists in a tutorial manner to the basics of modeling of electrochemical systems based primarily on diffusion equations. There is an introduction to analytical and numerical methods with examples taken from typical electrochemical experiments. The Laplace transform is used to derive the Cottrell equation and chronopotentiometry. The response of an electrode to a Gaussian concentration profile is detailed. Laplace’s equation is solved for a simple cell to determine the potential distribution. Discrete methods are employed to calculate the current time behavior following a potential step using the explicit finite difference method. Cyclic voltammetry is …