1,721,406 research outputs found
Nanomaterials and analytical chemistry
No full textNanomaterials play an important role in the area of sensor technology. In fact the sensitivity and the signal-to-noise ratio of many chemical sensors are significantly improved using nanomaterials. They have allowed the introduction of many strategies in sensors and biosensor technology. Recently, catalytic nanomotors were used for drug delivery, showing an oriented motion into the cells when they are assembled using magnetic nanowires. In this review, detailed bibliographic references are presented concerning the assembling of nanomaterial-based sensors, and a brief discussion about the potential health risk of nanoparticles will be also presented
Does lignin last 2000 years? Toward the understanding of oxidative degradation processes in archaeological wood: P-31 NMR spectroscopy of ancient Egyptian maufacts
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CYCLIC ENZYMATIC DETERMINATION OF L-LACTATE BY DIFFERENTIAL PH MEASUREMENT
No full textAn electrochemical procedure for the analysis of L-lactate based on the lactate dehydrogenase/lactate oxidase reaction cycle has been developed and applied in whole blood and wine. The reaction of lactate with lactate oxidase produces pyruvate, which is the substrate, at physiological pH, of the enzyme lactate dehydrogenase. This enzyme, in the presence of NADH, converts pyruvate to lactate consuming H+ An automated software controlled differential pHmeter was used for H+ detection and the Delta pH measured was correlated to the lactate concentration present in the sample. Lactate was measured in the range 0.4-20 mmol/L with a detection limit of 0.2 mmol/L. Recovery studies have been carried out to evaluate the effect of blood and wine matrices on lactate determination. The recovery was between 94 and 104% in blood and 93 and 104% in wine. Analysis of lactate in blood and wine samples has been carried out. Comparison with a reference spectrophotometric procedure has been reported and discussed.[...
Determinazione di composti di interesse enologico con biosensori basati su elettrodi stampati
No full textAmperometric ammonium ion and urea determination with enzyme-based probes
No full textAmperometric enzyme probes for ammonium and urea have been assembled and evaluated using immobilized glutamate dehydrogenase and urease enzymes coupled with platinum electrodes. Analytical parameters such as pH, buffer, temperature, probe life-time, enzyme immobilization, cofactor concentration and response time have been optimized. Ammonium was detected in the range 10(-5)-3 x 10(-4) mol l(-1). Better reproducibility and stability were achieved using the enzyme GLDH type III and NADH at a concentration of 10(-3) mol l(-1). Urea has been determined in the range 10(-5)-3 x 10(-4) mol l(-1) using the enzyme urease first in solution and then immobilized on nylon net. The analysis was based on an amperometric measurement which gives a linear relationship between current and analyte concentration. This considerably improved the sensitivity of the analysis when compared with the potentiometric-based procedures. Moreover, this method does not suffer from the potassium ion interference which affects the potentiometric nonactin-based NH4+ electrodes. Analysis of ammonium and urea were carried out in standard solutions and in saliva samples. Results compared with a spectrophotometric reference procedure correlated well.[...
NONINVASIVE BIOSENSORS FOR INVIVO AND EXVIVO ANALYSIS
No full textMeasurements of metabolites in media other than blood are becoming increasingly important because of the growing demand for non-invasive analysis, especially for patients who require daily monitoring of such parameters as glycemia and urea and, generally, for people from whom it is difficult to collect blood (including hemophiliacs, neonates and the elderly).[...
Screen-printed enzyme electrodes for the detection of marker analytes during wine-making
No full textReport on the 3rd Workshop of the European Union Concerted Action - Evaluation/Validation of Novel Biosensors in Real Environmental and Food Samples, Maó, Menorca (Balearic Island), Spain, November 2-4, 2003
No full textReport on the 8th International Symposium on Kinetics in Analytical Chemistry Rome, Italy, July 8-10, 2004
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