BaMoO4:Eu (BEMO) powders were synthesized by the polymeric precursor method (PPM), heat treated at 800 °C for 2 h in a heating rate
of 5 °C/min and characterized by powder X-ray diffraction patterns (XRD), Fourier Transform Infra-Red (FTIR) and Raman spectroscopy,
besides room temperature Photoluminescence (PL) measurements. The emission spectra of BEMO samples under excitation of 394 nm
present the characteristic Eu3+ transitions. The relative intensities of the Eu3+ emissions increase as the concentration of this ion increases from 0.01 to 0.075 mol, but the luminescence is drastically
quenched for the Ba0.855Eu0.145MoO4 sample. The one exponential decay curves of the Eu3+ 5D0→7F2 transition, λexc = 394 nm and λem = 614 nm, provided the decay times of around 0.54 ms for all samples. It was observed a broadening of the Bragg reflections
and Raman bands when the Eu+3 concentration increases as a consequence of a more disordered material. The presence of MoO3 and Eu2Mo2O7 as additional phases in the BEMO samples where observed when the Eu3+ concentration was 14.5 mol%. 相似文献
It has been possible to perform the simultaneous determination of choline and glucose using the intrinsic fluorescence of
the corresponding enzyme as an analytical signal. This can be done in two ways. First, for low glucose and choline concentrations
(about 0.55 mM and 0.75 μM respectively) two differentiated signals, without mutual interference, are obtained for both analytes
in the same measurement. Second, when glucose and choline concentrations are higher, a new model has been designed which permits
the concentrations to be accurately determined in samples containing from 0.55 mM to 3.75 mM glucose and from 0.75 μM to 11.0 μM
choline; the method has been applied to simultaneous glucose and choline determinations in serum samples with good results.
This method gives a better performance than multivariate calibration based on Partial Least Squares Regression. The methodology
here shown could be also used for the simultaneous determination of other pairs of analytes.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
A new strategy, epoxide-assisted precipitation route presented in this work, allows the shape control synthesis of Co3O4 nanoparticles. The shape of the nanoparticles is determined by the nature of the precursor cobalt salts (Co(NO3)2 · 6H2O, CoCl2 · 6H2O) used for the preparation of the particles. The different reaction dynamics of the two salts in ethanolic and aqueous solutions
with propylene oxide result in precursor particles with different structures, which lead to the formation of oxide nanoparticles
with different shapes during the heat treatment. Spherical particles of about 20 nm are obtained from the ethanolic solution
of Co(NO3)2 · 6H2O; cubic-shaped particles of about 30 nm can be prepared from the ethanolic solution of CoCl2 · 6H2O; whereas platelet-like particles of more than 100 nm are synthesized from the aqueous solution of the mixture of Co(NO3)2 · 6H2O and CoCl2 · 6H2O. 相似文献
Plasma membrane Ca2+-ATPases (PMCAs) are high affinity Ca2+ transporters actively involved in intracellular Ca2+ homeostasis. Considering the critical role of Ca2+ signalling in neuronal development and plasticity, we have analyzed PMCA-mediated Ca2+-ATPase activity and PMCA-isoform content in membranes from mouse cortex, hippocampus and cerebellum during postnatal development. 相似文献
Heparin detective : Silica nanoparticles functionalised with ion‐channel scaffolds were prepared and used for the chromofluorogenic sensing of heparin in aqueous environments (see figure). The surface of the nanoparticles was functionalised with polyamines (binding sites) and thiols. The reaction of a dye (squaraine) with the surface thiol groups was selectively inhibited by the coordination of heparin with the partly protonated polyamines.
A simple, reproducible, and efficient liquid chromatographic method was developed with UV detection. Water (0.05% TFA):acetonitrile
(0.05% TFA) was used as the mobile phase in a gradient system for the determination of procyanidin B2 (PB2) and epicatechin
(EC) in the bark of Guazuma ulmifolia Lam. The analysis was performed using a Phenomenex Gemini RP C18 column (5 μm) as stationary phase, at 30 °C, with a flow rate of 0.8 mL min−1, at a wavelength of 210 nm for detection and determination. The main validation parameters of the method were also determined.
Calibration curves were found to be linear, with ranges of 20.00–150.00 (PB2) and 10.00–110.00 μg mL−1 (EC). The correlation coefficients of linear regression analysis were between 0.9981 and 0.9988, and the detection limits
were between 2.89 and 2.54 μg mL−1. The contents of PB2 and EC were successfully determined, with satisfactory reproducibility and recovery. Recoveries of the
PB2 and EC were 103.00 and 104.01%, respectively. The method was successfully applied to the determination of procyanidins
in the bark of G. ulmifolia. 相似文献
A simple, reproducible, and efficient liquid chromatographic method was developed with UV detection. Water (0.05% TFA):acetonitrile (0.05% TFA) was used as the mobile phase in a gradient system for the determination of procyanidin B2 (PB2) and epicatechin (EC) in the bark of Guazuma ulmifolia Lam. The analysis was performed using a Phenomenex Gemini RP C18 column (5 μm) as stationary phase, at 30 °C, with a flow rate of 0.8 mL min−1, at a wavelength of 210 nm for detection and determination. The main validation parameters of the method were also determined. Calibration curves were found to be linear, with ranges of 20.00–150.00 (PB2) and 10.00–110.00 μg mL−1 (EC). The correlation coefficients of linear regression analysis were between 0.9981 and 0.9988, and the detection limits were between 2.89 and 2.54 μg mL−1. The contents of PB2 and EC were successfully determined, with satisfactory reproducibility and recovery. Recoveries of the PB2 and EC were 103.00 and 104.01%, respectively. The method was successfully applied to the determination of procyanidins in the bark of G. ulmifolia.
An accurate, simple, reproducible, and sensitive liquid chromatographic method was developed and validated for the captopril determination in controlled release tablets. The analyses were performed at room temperature on a reversed-phase Phenomenex Luna C18 column (250 mm × 4.6 mm). The mobile phase was composed of water:methanol (45:55; v/v) pH 2.5, and it was eluted isocratically at a 1.0 mL min−1 flow rate. The method was validated in terms of specificity, linearity, quantification limit, detection limit, accuracy, precision and robustness. The response was linear in the range 0.3–1.5 mg mL−1 (r2 = 0.9983). The relative standard deviation values for inter-and intra-day precision were 0.77% and 0.50%, respectively. Recoveries ranged between 97.7 and 99.1%. The method was successfully applied for the determination of captopril in the developed formulations.