Novel Oxygen Selective Complexes for Optical Oxygen Sensing

Novel optical sensing films for oxygen based on highly luminescent iridium (III) and ruthenium (II) complexes have been developed. These demonstrate excellent long-term photostability (several months) when incorporated into polystyrene membranes. The influence of different plasticizers on the specific luminescence quantum yield, the Stern–Volmer constant, the reversibility and the response time were evaluated. Additionally the sensing films can be sterilized by chemical cleaning and gamma-ray irradiation

Solution NMR and X-Ray Structural Studies on Model Iron Phthalocyaninato-Complexes for Use as Optical Sensors

The addition of primary amines as solubilizing reagents for phthalocyaninatoiron complexes is shown to afford six-coordinate bis(amine)phthalocyaninato complexes, i.e., [Fe(amine)2(pc)] 2 (amine = decan-1-amine) and 3 (amine = benzylamine), with the two new N-donors occupying the trans-axial positions. The new complexes were characterized by extensive NMR measurements in THF solution. For complex 3 with the benzylamine ligand, the solid-state structure was determined by X-ray diffraction methods. Complex 2 is sufficiently labile in THF solution to exchange one amine ligand against CO (gas) affording an equilibrium mixture containing [Fe(amine)(CO)(pc)] 4

l -Glutamate biosensor for estimation of the taste of tomato specimens

Abstract An amperometric biosensor has been developed for measurement of Umami, or the taste based on the amount of l-glutamate, in tomato foods. The biosensor is based on an enzyme-mediator system in which l-glutamate oxidase is used for biochemical oxidation of l-glutamate and a tetrafulvalene-tetracyanoquinodimethane (TTF-TCNQ) paste, prepared from the mixture of TTF-TCNQ salt, graphite powder, and silicone oil, serves as the mediator. The limit of detection, calculated by use of a four-parameter logistic model, was 0.05 mmol L-1, and the limit of quantification was 0.15 mmol L-1. The correlation coefficient (R 2) was 0.990 and the relative standard deviation was no more than 1% (n=5). The response time (t 95) was 20–50 s, depending on concentration. The repeatability of the sensor was better than 5% (n=10). The sensor developed was stable for more than ten days

Fluoro Reactands and Dual Luminophore Referencing: A Technique To Optically Measure Amines

An optical sensor for aqueous 1-butylamine is presented which combines two novel techniques: A fluorescent indicator dye (fluoro reactand) embedded in a thin polymer layer performs a reversible chemical reaction with the analyte, causing changes in luminescence intensity. At the same time, inert phosphorescent beads dispersed within the polymer layer provide luminescence signals that act as an internal reference for the indicator dye. As a consequence, the optical sensor is independent of light source fluctuations, ambient light, drifts in optoelectronic setup, or optical fiber bending