Immuno-arrays for multianalyte analysis of chlorotriazines

In this paper, a novel strategy for multicomponent analysis of two classes of pesticides such as triazines (atrazine and simazine) and phenoxyalkanoic acids (2,4-dichlorophenoxy acetic acid (2,4-D), 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), 4-chlorophenoxyacetic acid (CPOAc), phenoxyacetic acid (POAc)) employing immuno-arrays is demonstrated. The approach is based on cross-reactive arrays of specific antibody pairs coupled to chemometric pattern recognition. The monoclonal antibody pairs employed in this work (atrazine-simazine and 2,4-D) are specific towards a set of analytes and preclude a particular set of others present in the sample matrix. Antibody pairs of atrazine, simazine, and 2,4-D are used to discriminate and quantify analyte of interest. Atrazine was quantified in presence of trace concentration of simazine and that of 2,4-D. The combinatorial cross-reactivity of antibody pairs towards simazine, atrazine and 2,4-D is used to distinguish among different classes of analytes and their influence on the signal suppression in immuno-techniques. These sensors exclude recognition by carbamates such as carbaryl and carbofuran.     

Characterization of electroplated ZnTe coatings

Zinc telluride (ZnTe) layers have been grown on conducting glass substrates using an electrochemical technique and characterized using cyclic voltammetry, X-ray diffractions, UV–vis-near infrared spectroscopy, and scanning electron microscopy (SEM). The reaction kinetics of binary film formation is also discussed. Cyclic voltammetry experiments were performed to elucidate the electrodic processes that occurred when potentials were applied and the optimum potential for electrodeposition were determined. X-ray diffraction studies revealed that the deposited films were polycrystalline in nature with zinc blende cubic structure. The various microstructural parameters were calculated using structural studies. The optical transmission and reflection spectrum were recorded and direct transition band gap energy is estimated about 2.26 eV by Tauc’s plot. The SEM pictures revealed that the nanoneedles protruding from nanorods with bunches of atoms agglomerate each other. The energy dispersive analysis by X-rays spectrum revealed the stoichiometry composition of ZnTe thin film at optimized preparative parameters.     

Phenothiazine-pyridyl chalcone: an easily accessible colorimetric and fluorimetric ‘on-off’ dual sensing probe for Cu

Phenothiazine-pyridyl chalcone, a new internal charge transfer (ICT) probe, has been designed that allows naked eye detection and a reversible, ratiometric ‘on-off’ sensing capability for biologically and environmentally significant Cu²⁺ in CH₃OH-H₂O (4:1 v/v) under buffered conditions. The association constants determined using spectrophotometric and the fluorimetric techniques follow the order Cu²⁺ > Ni²⁺ > Co²⁺ > Zn²⁺ > Cd²⁺ > Mg²⁺ ≈ Ba²⁺ ≈ Ca²⁺ ≈ K⁺≈ Na⁺ ≈ Li⁺.     

Study of mixed complexes by polarography—copper-glycine-α-alanine and cadmium-ammonia-pyridine complexes

The method of DeFord and Hume for the study of complexes by polarography has been extended to the study of mixed complexes of copper-glycine-α-alanine and cadmium-ammonia-pyridine.     

Solvent extraction studies of indium

Solvent extraction of indium from malonic acid medium by Primene JM-T has been studied. The extraction has been studied as a function of pH and concentrations of malonic acid and sodium malonate. The nature of the acid-amine complex has been established by chemical analysis and by the application of the method of Hogfeldt and Fredlund. The equilibrium constant for the reaction has also been calculated. The nature of the indium complexes getting extracted has also been discussed.     

Study of indium complexes by solvent extraction and ion exchange

Complexes of indium with hydroxy carboxylic acids like glycollic, mandelic and thioglycollic acids have been investigated by the method of competitive reactions using HTTA as the auxiliary ligand. An ion exchange study has been made in some cases to confirm the results. An ion exchange study of indium fluoride complexes has also been made. The data have been analysed for the stability constants of the indium complexes.     

Study of theS-matrix near bound states in the continuum

The behaviour ofS-matrix for potentials generating bound states in continuum in the neighbourhood of the positive bound state energies is studied. It is shown that unlike the case of usual negative energy bound states, theS-matrix does not have a pole at the positive bound state energy but becomes unity at the energy corresponding to bound states in continuum. Calculations ofS-waveS-matrix for a local potential constructed by Stillinger and Herrick and a separable nonlocal potential constructed by the present authors verify these results. Our results indicate that the bound states embedded in continuum constructedvia the von Neumann and Wigner procedure cannot be interpreted as resonances with zero width.