Chemistry Commons^™

Optimising Design Parameters Of Enzyme-Channelling Biosensors, Dana Mackey, Tony Killard

Conference Papers

Two mathematical models for an electrochemical biosensor are proposed and compared with a view to determining the ratio of two immobilized enzymes which maximizes the amperometric signal amplitude.

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 …

Contextualising Nanotechnology In Chemistry Education, Christine O'Connor, Hugh Hayden

Articles

This paper will give an example of a pedagogical approach taken in integrating nanotechnology into a chemistry degree course. In recent years nanotechnology has widely become part of the course content for undergraduate chemistry and physics degree curriculum. How contextualised the delivery of the subject matter may vary. The role of contextualisation of nanotechnology in the delivery of the content is the main focus of this paper, as to date in Ireland and many other countries nanotechnology has not been integrated into many chemistry degree courses but is slowly becoming the case. An evaluative methodology of the pedagogical approach for …

Development And Evaluation Of Passive Sampling And Lc-Ms Based Techniques For The Detection And Monitoring Of Lipophilic Marine Toxins In Mesocosm And Field Studies, Elie Fux

Doctoral

The consumption of shellfish that accumulate marine biotoxins produced by harmful Algae can result in severe gastrointestinal or neurotoxic illnesses depending on the nature of the toxin. Therefore, it is essential that suitable monitoring programs are implemented in order to protect public health. This PhD study focused on aspects of the characteristics and monitoring of azaspiracids and toxins from Dinophysis spp. Passive samplers were used in this study in parallel with both indigenous and transplanted mussels that did not contain toxins to investigate the accumulation of toxins on the West coast of Ireland during 2005. This approach allowed for a …

Novel Photoelectrochemical Cell For The Remediation Of Organic Compounds In Water, Patrick Enright

Doctoral

Titanium dioxide (TiO2) suspensions have widely been used as photocatalysts, either alone or in a doped form to degrade organic compounds and kill bacteria. Because of its relatively large band gap, UV light has been the most efficient radiation used to allow this catalysis to occur. TiO2 has also been immobilised on electrodes in order to separate the ‘reduction’ and ‘oxidation’ reactions. Typical systems involve the oxidation of a ‘fuel’ at a TiO2 coated anode and the reduction of oxygen at a separate cathode, where the passage of current can be monitored, and this work utilises such a system. In …

Systematic Synthesis And Study Of The Structure-Property Relationships Of Arylene Vinylene Polymers., Patrick Lynch

Doctoral

Much is known about the electronic, vibrational and steric effects resulting from the addition of differing organic functional groups as side chains, to the parent conjugated polymer. However the same cannot be said about the substitution of constituents of the polymer backbone itself. To this end a study is presented here which systematically studies the effects of naphthalene and anthracene substitution of the properties of poly phenylene vinylene (PPV) derivative conjugated polymers. The synthesis by the Witting-Horner reaction of derivatives is presented whereby the phenylene units of the PPV structure are methodically substituted by naphthylene and anthrylene units to form …

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.

Prevention Of Staphylococcus Epidermidis Biofilm Formation Using A Low-Temperature Processed Silver-Doped Phenyltriethoxysilane Sol–Gel Coating, Niall Stobie, Brendan Duffy, Declan Mccormack, John Colreavy, Martha Hidalgo, Patrick Mchale, Steven Hinder

Articles

Sol–gel coatings which elute bioactive silver ions are presented as a potential solution to the problem of biofilm formation on indwelling surfaces. There is evidence that high-temperature processing of such materials can lead to diffusion of silver away from the coating surface, reducing the amount of available silver. In this study, we report the biofilm inhibition of a Staphylococcus epidermidis biofilm using a low-temperature processed silver-doped phenyltriethoxysilane sol–gel coating. The incorporation of a silver salt into a sol–gel matrix resulted in an initial high release of silver in de-ionised water and physiological buffered saline (PBS), followed by a lower sustained …

The Development Of A Quality Risk Management Solution Designed To Facilitate Compliance With The Risk-Based Qualification, Validation And Change Control Gmp Requirement Of The Eu, Kevin O'Donnell

Doctoral

This research work was concerned with investigating the risk-based regulatory requirements that are currently in place in the European Union governing the manufacture of medicinal products. The main goal of this research was to develop a practical Quality Risk Management methodology that served as a solution for facilitating compliance with the EU GMP requirements in the area of risk-based Qualification, Validation and Change Control, and which was fully in line with the principles and guidance of ICH Q9, on Quality Risk Management. Following extensive testing and evaluation activities with a range of key stakeholders including the pharmaceutical manufacturing sector in …

Enhancing Forensic Science Context-Based Laboratory Activities For Undergraduate Chemistry Students, Sarah Cresswell, John Fox, Claire M. Mcdonnell, Christine O'Connor, Cora O'Donnell, Michael K. Seery

Conference Papers

This paper discusses the development of student centred context-based practical activities for use in third level Forensic Science/ Chemical Analysis courses.

Metallopharmaceuticals As Photoactivatable Anticancer Drugs, Samar Moqadasi, Christine O'Connor, Denis O'Shea, Michael Devereux

Conference Papers

Target-based research (treating infected site only), directed towards the design and mechanism of action of metal-based anticancer complexes is expanding rapidly due to the selectivity and activity of such novel therapeutics. The photo activation of Ruthenium (II) complexes as therapeutic drugs has recently escalated as the complexes are suitable for photoactivation due to their well published photochemical and photophysical properties which in turn is the basis of photodynamic approaches to therapy.1-5 The aim of this study is to synthesise a series of metallo-complexes of which will be tested on tumour and non-tumour cell lines in the Radiation & Environmental Science …

Metallo-Cyclodextrin Complexes For The Separation Of Chiral Materials, Synthesis And Characterisation, Ciaran Francis Potter

Doctoral

The processes of separation and detection of chiral compounds are extremely important in the pharmaceutical industry. This study aims to investigate a safe and variable methods for the separation of the two enantiomers of the drug DOPA (Dihydroxyphenylalanine). L-DOPA is the most effective drug at present used to combat Parkinson’s disease while D-DOPA is inactive, thus for drug efficacy only the single biologically active enantiomer should be present in the formulation. In this work, cyclodextrins (CDS) were utilised fro their ability to act as a host for guest species, acting in the role as both a first and second sphere …

Continuous Improvement In E-Learning: Investigating The Effect And Impact Of Our Webct Chemistry Support Initiative (Csi) And Implications For Further Enhancement Of The Virtual Learning Environments (Vles) Developed, Christine O'Connor, Claire M. Mcdonnell, Michael K. Seery

Conference Papers

A Virtual Learning Environment (VLE) was developed using WebCT software and was piloted in 2004 in the School of Chemical and Pharmaceutical Sciences in DIT by the authors. This was one of a number of measures introduced with the aim of supporting and retaining first year undergraduates on the Science ordinary degree programme and was designed as a Chemistry Support Initiative (CSI) for first year Chemistry learning and teaching (O’Connor, 2005). This work was supported through funding from the DIT Learning and Teaching Centre which allowed a summer research assistant to be taken on. Since the launch of the first …

Synthesis And Characterisation Of Tetra-Tetrazole Macrocycles, Andrew Bond, Adrienne Fleming, Fintan Kelleher, John Mcginley, Vipa Prajapati, Signe Skovsgaard

Articles

The syntheses of tetra-tetrazole macrocycles, containing two bis-tetrazole units linked by a variety of alkyl chain lengths from four to eight carbons, are described. The crystal structures of three of these derivatives are reported, and the molecular conformation in the solid state is compared to that of one previously reported tetra-tetrazole macrocycle and to other bis- and tris(tetrazole)benzene structures. The macrocycle conformation is influenced by the length of the alkyl chain linker, the relative orientation of the tetrazole rings on the benzene ring, and by intermolecular interactions. In the macrocycles based on 1,2-bis(tetrazole)benzene, the adjacent tetrazole rings on the benzene …

A Novel Processing Route For The Production Of Nanoparticulate Zinc Oxide Using An Isophthalate Precursor, Grainne Duffy, Declan Mccormack, Suresh Pillai

Articles

Zinc oxide nanoparticles have been processed from a novel isophthalate precursor. In contrast to those processed from an oxalate precursor, this material exhibits three-dimensional, non-directional aggregation behaviour.

Such non-directional aggregation of uniaxial crystallites may allow for the production of structures with a higher proportion of catalytically active surfaces than can be prepared through conventional sol–gel methods. XRD,

FTIR, TEM and SEM were used to characterize the synthesized materials.

Zinc oxide particles synthesized by using isophthalic acid (C6H4-1,3-(COOH)2) are found to be slightly smaller than the previously reported materials prepared through chelation with oxalic acid (H2C2O2・2H2O).

Silver Doped Titanium Dioxide Nanomaterials For Enhanced Visible Light Photocatalysis, Michael Seery, Reena George, Suresh Pillai, Patrick Floris

Articles

This paper presents a systematic study on two different preparation methods for titanium dioxide with silver. The silver can be incorporated by irradiating the reaction mixture during preparation to reduce silver ion to silver metal or by direct calcination of the sol–gel material to decompose silver nitrate to silver. Of the two methods, we found the latter produces a more effective photocatalytic material (6–50% improvement in catalytic efficiency), which is attributed to the fact that the silver is homogeneously dispersed throughout the material. The efficiency of the materials were examined using a Q-Sun solar simulator (visible light) and in Dublin …

Use Of The Mitsunobu Reaction In The Synthesis Of Orthogonally Protected A,B-Diaminopropionic Acids, Fintan Kelleher, Keith Ó Proinsias

Articles

Orthogonally protected a,b-diaminopropionic acids have been synthesised in good yields by the reaction of N-trityl L-serine esters with N-substituted sulfonamides under Mitsunobu reaction conditions (DEAD, PPh₃, THF). The best isolated yields were obtained when N-Boc p-toluenesulfonamide was used as the nitrogen nucleophile precursor in the Mitsunobu reaction. Subsequently, the N-trityl group was efficiently replaced with the more stable allyloxycarbonyl (alloc) group.

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 …

Rate And Equilibrium Constants For Reactions Of Coordinated Cyclohexadienyl Cations, Martin Galvin

Doctoral

In this work, the nucleophilic reactions of ironcarbonyl coordinated cyclohexadienyl cations with water and hydroxide to produce the corresponding coordinated arene hydrate analogues was examined. These nucleophilic reactions are a key step in a synthetic route to convert arene cis-dihydrodiols to their trans-isomers via their tricarbonyliron coordinated complexes. The arene trans-dihydrodiols produced have significant potential to be used as chiral buildings blocks in synthetic chemistry and have the advantage that they are more stable then their cis-analogues The first cation studied was (п5-cyclohexadienyl)dicarbonyl-triphenylphosphineiron. An equilibrium constant, pKr, for formation of the coordinated arene hydrate (п4-exo-5-hydroxy-1,3-cyclohexadience)dicarbonyltriphenylphosphine-iron, from this coordinated cation was …

Matrix Effects, Development Of Clean-Up And Lc-Techniques Contributing Towards A Reference Lcms Method For The Analysis Of Lipophilic Marine Toxins, Mairead Anne Mcelhinney

Masters

The most widely used reference method in Europe for the detection and monitoring of lipophilic marine toxins is the Mouse Bioassay (MBA) as first described by Yasumoto et al., (1978). The MBA offers a good level of protection to human health and is capable of detecting the overall toxicity of previously known toxins. However, there are drawbacks associated with the use of the MBA as it is both expensive and time consuming and can give false positives due to interferences (Suzuki et al, 1976). The problems associated with the original mouse bioassay have led to several modifications (Yasumoto et al, …

Incompressible And Compressible Boundary Layers On A Fibre In The Melt Spinning Process, John Harding

Doctoral

This thesis seeks to investigate shear stress on and heat transfer from the surface of a fibre in the industrial process of melt spinning. Melt spinning is the process whereby molten polymer materials are extruded through the holes of a device known as a spinneret to create continuous filaments of polymer. Fibres manufactured in this way are used in applications as diverse as fashion and clothing, to telecommunications. The magnitude ofthe shear stress on the fibre surface, and also the rate of heat transfer from the fibre to the surrounding environment are of major importance to the overall quality of …

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 Novel Tio2 / Pvc Layer For Use In A Photoelectrochemical Cell, Faiza Touati, John Cassidy, Kevin Mcguigan

Articles

A novel method of coating titanium dioxide on a glassy carbon electrode as a polyvinylchloride composite , is described. On illumination , there is an enhanced voltammetric current at this TiO2/PVC composite in aqueous formic acid solution. This electrode is used as the basis of a formic acid fuel cell where oxygen is reduced at a platinum cathode. The system yields 100 cm-2 for 0.01 mol dm-3 HCOOH in 0.1 mol dm-3 NaOH under illumination from a 150 W xenon lamp. The current without illumination is 0.5 cm-2.

Newly Identified Vitamin K-Producing Bacteria Isolated From The Neonatal Faecal Flora, Gordon Cooke, John Behan, Mary Costello

Articles

Fat-soluble vitamin K is an essential component of the blood clotting process. Menaquinones are the naturally occurring form of vitamin K identified in bacteria. Lipid extracts were made from three bacteria originally isolated from the human neonatal gut and identified as Enterobacter agglomerans, Serratia marcescens and Enterococcus faecium. Following preparative thin layer chromatography (TLC), the lipid extracts were subjected to liquid chromatography-mass spectrometry (LC-MS) analysis. Peak analysis of the LC-MS data showed that the three bacteria produce various forms of menaquinone.

Implications Of Mass Education On Chemistry Higher Education, Christine O'Connor

Articles

The following paper discusses the implications of government policy for widening access and participation in third level institutes. The increase in ‘non-traditional’ students has been widely recognised on an international scale; however, some issues of inequality still exist. The ‘struggles’ associated with widening participation and the creation of a ‘new’ student type are discussed, with particular reference to chemistry education. A change is needed with regard to the pedagogical approach taken by staff in order to cater for a diverse student body comprising a broad range of learner types, and this must be supported both at departmental and institutional levels. …

The Synthesis Of Zinc Oxide By Direct And Indirect Methods, Grainne Duffy

Masters

The synthesis of zinc oxide through three routes was investigated; carboxylic acid chelation, polymer assisted synthesis in an alcoholic medium and slow thermolysis of precursor. In the case of carboxylic acid chelation, it was determined that the rate at which the precursor is formed has a significant effect on the quality of zinc oxide particles produced. Investigation of the effect of concentration, pH and species of chelating agent used on the purity and structure of product was undertaken. Examination of the composition and morphology of materials produced revealed the presence of single-crystalline spheres, the packing density and aggregation morphology of …

Spirobicyclic Diamines 2: Synthesis Of Homochiral Diastereoisomeric Proline Derived [4,4]-Spirolactams, Fintan Kelleher, Sinead Kelly

Articles

L-Proline derived diastereoisomeric [4.4]-spirolactams have been prepared by a reductive-amination reaction of (R)- or (S)-alanine methyl ester followed by thermal cyclisation of the resulting amine onto the proline ester group in refluxing toluene. Under similar conditions (R)- or (S)-phenylalanine methyl ester gave no cyclisation products, while R- or S-a-methylbenzylamine required treatment with NaNH₂ in refluxing toluene to induce cyclisation giving diastereoisomeric [4.4]-spirolactams

Spirobicyclic Diamines 1: Synthesis Of Proline-Derived Spirolactams Via Thermal Intramolecular Ester Aminolysis, Fintan Kelleher, Sinead Kelly

Articles

Proline derived [4.4]-spirolactams have been synthesised in good yields by a reductive-amination reaction followed by thermal cyclisation of the resulting amine onto the proline ester group in refluxing toluene. The synthesis of the corresponding [4.5]-spirolactams by the same method gave much reduced yields.

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 …

Solubilisation, Purification And Processing Of Single Walled Carbon Nanotubes Using Organic Molecules, Theresa Hedderman

Doctoral

The aims of this research are seven fold; • To enhance the solubility of SWNTs in organic solvents. • To purify an untreated sample of SWNTs that contains many side products. • To gain a greater understanding of the interaction between the polycyclic aromatic hydrocarbons and SWNTs. • To debundle and disperse SWNTs. • To select SWNTs of a specific structure based on the structures of the polycyclic aromatic hydrocarbons used. • To observe and compare the interaction of polycyclic aromatic hydrocarbons with SWNTs produced by different methods. • To elucidate factors which contribute to different degrees of interaction between …