Entity

Time filter

Source Type


Munoz J.A.,Center Grup Of Tecniques Of Separacio En Quimica Gts | Lopez-Mesas M.,Center Grup Of Tecniques Of Separacio En Quimica Gts | Valiente M.,Center Grup Of Tecniques Of Separacio En Quimica Gts
Talanta | Year: 2010

Oxalate, citrate, uric acid and creatinine are important urine markers for the evaluation and treatment of urolithiasic patients. They have been traditionally analysed by enzymatic and chromatographic techniques which present practical drawbacks, mainly in the sample pre-treatment step. The purpose of this study was to evaluate those markers in urine samples, by an easy multi-analyte assay using capillary zone electrophoresis. The four urine metabolites were determined, at 25 °C, by using a 50 cm × 75 μm capillary in 50 mmol l-1 phosphate buffer (pH 6.5), at constant voltage of -30 kV and UV detection at 195 nm (for oxalate and citrate) or 30 kV and 234 nm (for creatinine and uric acid). The sample pre-treatment was minimum, 5- and 20-fold dilution of the urine sample and acidification to pH 3-4. Validation parameters (linear range, sensitivity, accuracy, precision and detection limits) were statistically comparable to those obtained with the official methods normally used in the clinical practice. The effect of freezing as a conservation method of urine samples is also discussed in terms of recoveries of the analytes. The analytical method developed is highly useful as a diagnostic tool for detecting metabolic renal disorders due to its simplicity, time consuming, easy automation, cost efficiency and analytical effectiveness, accomplishing with the clinical requirements. © 2010 Elsevier B.V. All rights reserved. Source


Soler L.,Center Grup Of Tecniques Of Separacio En Quimica Gts | Candela A.M.,Center Grup Of Tecniques Of Separacio En Quimica Gts | Macanas J.,Center Grup Of Tecniques Of Separacio En Quimica Gts | Munoz M.,Center Grup Of Tecniques Of Separacio En Quimica Gts | Casado J.,Center Grup Of Tecniques Of Separacio En Quimica Gts
International Journal of Hydrogen Energy | Year: 2010

A new process to obtain H2 from H2O using Al corrosion in Na2SnO3 solutions is described. Results showed an enhancement of H2 production rates using Na2SnO3 instead of NaOH at the same pH. A side reaction of Al in Na2SnO3 solutions has been found, which consumes Al to produce metallic Sn. H2 yield depends chiefly on Al/Na2SnO3 molar ratio for experiments with Na2SnO3 concentrations above 0.025 M, reaching higher yields with higher Al/Na2SnO3 ratios. The maximum H2 production rates are proportional to the initially added Al mass. Two different shrinking core models for examining the kinetics of H2 generation are verified and the activation energy (Ea) is 73 ± 6 kJ mol-1, confirming a rate control by a chemical step. A mechanism of Al corrosion in Na2SnO3 solutions is proposed and compared with the mechanism in NaOH and NaAlO2 solutions. © 2009 Professor T. Nejat Veziroglu. Source

Discover hidden collaborations