Résultats exploitables Novel bonded oxides with covalently immobilised organic ligands for chemical sensors development A set of materials (around 100 compounds) based on silica with immobilised luminescent dyes have been obtained. The dyes were designed to be selective for important pH region (6-9) and for interaction with toxic metal ions in water. Different modified silicon oxide matrixes were used to improve stability, selectivity and sensitivity of the dyes. For developing optical sensors few configuration of membrane that incorporate optically active materials were tested: transparent films and bids, resistible slides and disks. Adsorption and fluorescent emission spectra were recorded from the most perspective materials. It was shown that fluorescence of some samples strongly depends on solution's pH and contamination of water by heavy metals. Chelating nature of modified silica increase sensitivity of sensors. It can be used for increasing analytical signal in diluted solutions. As a prototype of metal-selective chemical sensor benzoilphenylhydrxylamine silica gel was used since correlation between iron concentration in water and optical response of the sensor was found. New chemically modified silica's with covalently bonded chelating groups of N-benzoyl-N-phenylhydroxylamine (SiO2-BPHA) were obtained in a three-step surface reaction. A chemisorption of hydrogen and some metal ions contaminations present in sea water (Fe(III), V(V), Cu(II), Mn(II), Co(II), Ni(II), Pb(II), Cd(II)) from aqueous media was investigated. From the results of a quantitative physicochemical analysis it was found that dissociation constant of bonded BPHA considerably rose in comparison with dissociation constants of analogs in solutions. Bonded complexes with all studied metals were less stable. Linear correlation between stability of complexes in solution and on the surface was found as log β(surf.) = log β(sol.) - 3.07. Strong fixation of counter-ions near surface charged groups was concluded from the experiment. SiO2-BPHA demonstrates high selectivity towards Fe(III) and V(V) with selectivity coefficient Fe/Cu = 150 and Fe/Cd = 105. Linear correlation was found between concentration of sorbed Fe3+ and Kubelka-Munk function from SiO2-BPHA that has been used for iron optical sensoring. Recherche de données OpenAIRE... Une erreur s’est produite lors de la recherche de données OpenAIRE Aucun résultat disponible
