Self-referenced luminescence thermometry with Sm(3+) doped TiO2 nanoparticles.

The performance of Sm(3+) doped TiO2 nanoparticles for luminescence temperature sensing was tested over a temperature range from room to 110 °C. The Sm(3+) ions were incorporated into TiO2 nanocrystals using hydrolytic sol-gel route. Microstructural characterization of the obtained material was performed using transmission electron microscopy and x-ray diffraction measurements. Luminescence emission spectra of Sm(3+) doped TiO2 nanoparticles consists of two distinct spectral regions: the high energy region associated with the trap emission of the TiO2 host, and the low energy region with well-resolved emission peaks of the Sm(3+) ions. The ratio between Sm(3+) emission and TiO2 trap emission shows strong temperature dependence, and is tested for temperature sensing. The relative sensor sensitivity was found to be higher than 1% °C(-1) over given temperature range with the maximum value of 10.54% °C(-1) at 57.5 °C. Lifetime data derived from the Sm(3+) emission decay revealed that time-resolved measurements provide comparable quality of temperature sensing as corresponding ratiometric measurements, with a maximum relative sensitivity of 10.14% °C(-1) at 66.5 °C.

Nanoparticle shape and configuration analysis by transmission electron tomography.

Tomographic reconstruction by transmission electron microscopy is used to reveal three-dimensional nanoparticle shapes and the stacking configurations of nanoparticle ensembles. Reconstructions are generated from bright-field image tilt series, with a sample tilt range up to +/- 70 degrees, using single or dual tilt axes. We demonstrate the feasibility of this technique for the analysis of nanomaterials, using appropriate acquisition conditions. Tomography reveals both cubic and hexagonal close-packing configurations in multi-layered arrays of size-selected In nanospheres. By tomography and phase-contrast lattice imaging, we relate the three-dimensional shape of PbSe octahedral nanoparticles to the underlying crystal structure. We also confirm simple-cubic packing in multi-layers of PbSe nanocubes and see evidence that the particle shapes have cubic symmetry. The shapes of TiO(2) nanorod bundles are shown by tomographic reconstruction to resemble flattened ellipsoids.

Gas chromatography-mass spectrometry determination of isosorbide 5-mononitrate and related impurities in raw materials and dosage formulations.

A straightforward quantitative method for gas chromatography-mass spectrometry determination of isosorbide 5-mononitrate (IS5MN) and its related impurities such as isosorbide (IS), isosorbide diacetate (ISDA) and isosorbide 2-acetate-5-nitrate (IS2A5N) in raw materials as well as in dosage formulations is developed. The recovery of these materials was found to be 100.4 +/- 2.4, 99.3 +/- 4.7, 97.8 +/- 5.2 and 100.1 +/- 3.1%, while the detection limits were 27.2, 1.26, 1.02 and 0.78 micrograms in dosage formulations for IS5MN, ISDA, IS2A5N, and IS, respectively. The applicability of the method was tested by analysing three different formulations of IS5MN.

Kinetics of the reaction of S-carboxymethyl-L-cysteine with palladium(II) chloride.

The influence of the acidity and the Cl- concentration on the kinetics of the complex formation between s-carboxymethyl-L-cysteine and Pd(II) chloride was studied with a stopped-flow technique in the pH range from 1.5 to 5.0 at 25 degrees C. The reaction mechanism involving Pd(H2O)4-nCln, LH-, LH2 and LH3+ species was proposed. Fairly good agreement between the computed and experimentally determined rate constants was found.