A novel route to copper(ii) detection using \u27click\u27 chemistry-induced aggregation of gold nanoparticles

A simple colorimetric method for the detection of copper ions in water is described. This method is based on the \u27click\u27 copper(i)-catalyzed azide-alkyne cycloaddition reaction and its use in promoting the aggregation of azide-tagged gold nanoparticles by a dialkyne cross-linker is described. Nanoparticle cross-linking, evidenced as a colour change, is used for the detection of copper ions. The lowest detected concentration by the naked eye was 1.8 μM, with the response linear with log(concentration) between 1.8-200 μM. The selectivity relative to other potentially interfering ions was evaluated

Surface enhanced Raman spectroscopy: substrate fabrication and applications to arsenic speciation

The toxicity of arsenic depends on its chemical form. Organo-arsenic compounds are acknowledged to be less toxic than inorganic arsenic compounds. Therefore, measurement of the concentration of arsenic as element (“total arsenic”) alone is insufficient because organo-arsenicals comprise an important fraction of many environmental samples.In this thesis several milestones on the path towards the development of a continuous and miniaturised arsenic speciation system based on surface enhanced Raman spectroscopy was achieved. The well known oxidation reduction cycle (ORC) technique for fabricating polycrystalline gold foils as effective surface enhanced Raman spectroscopy (SERS) substrates was systematically optimised using a central composite experimental design (CCD). A novel one step electrochemical method, which has been developed for fabrication of nano-porous gold films (NPGF), was demonstrated and optimised as an effective alternative to ORC.Direct-write electron beam lithography and metal-lift-off nanofabrication techniques were also used to create gold nano-pillar systems which serve as SERS substrates. The CCD optimisation model, built from the dimensions of the pillars and the distance between them predicts that higher Raman signal enhancements can be obtained using arrays with 185 nm spacing and 214 nm x 214 nm dimensions.A Raman spectroscopic study of twelve organo-arsenics was reported. The prediction of the normal mode vibrational frequencies and assignments were based on calculations done at the HF, DFT/B3LYP levels of theory using 6-311++G(3df,3pd) basis set.The first multivariate detection of the concentration of arsenic species using SERS was demonstrated. The adsorption of arsenic species on the surface has been aided by selecting the arsenic species according to their ionic charges. The species were partitioned into monolayers of charged alkanethiols. Multivariate regression of pure arsenic species over the concentration range of 0 – 5 mM was shown using a PLS1 algorithm. Simultaneous determination of arsenate and arsenobetaine has been demonstrated using a two sensor system. PLS2 was used for calibration of 16 samples containing all the possible combination of the chosen concentration range. The PLS2 model was applied to adequate amount of independent test sets and the actual concentration of the test sets agreed well with the predicted concentration

A novel route to copper(ii) detection using 'click' chemistry-induced aggregation of gold nanoparticles

A simple colorimetric method for the detection of copper ions in water is described. This method is based on the 'click' copper(i)-catalyzed azide-alkyne cycloaddition reaction and its use in promoting the aggregation of azide-tagged gold nanoparticles by a dialkyne cross-linker is described. Nanoparticle cross-linking, evidenced as a colour change, is used for the detection of copper ions. The lowest detected concentration by the naked eye was 1.8 µM, with the response linear with log(concentration) between 1.8-200 µM. The selectivity relative to other potentially interfering ions was evaluated

Experiences with a researcher-centric ELN

Electronic Laboratory Notebooks (ELNs) are progressively replacing traditional paper books in both commercial research establishments and academic institutions. University researchers require specific features from ELNs, given the need to promote cross-institutional collaborative working, to enable the sharing of procedures and results, and to facilitate publication. The LabTrove ELN, which we use as our exemplar, was designed to be researcher-centric (i.e., not only aimed at the individual researcher's basic needs rather than to a specific institutional or subject or disciplinary agenda, but also able to be tailored because it is open source). LabTrove is being used in a heterogeneous set of academic laboratories, for a range of purposes, including analytical chemistry, X-ray studies, drug discovery and a biomaterials project. Researchers use the ELN for recording experiments, preserving data collected, and for project coordination. This perspective article describes the experiences of those researchers from several viewpoints, demonstrating how a web-based open source electronic notebook can meet the diverse needs of academic researchers