Optical Sol-Gel-Based Dissolved Oxygen Sensor: Progress Towards a Commercial Instrument

A dissolved oxygen sensor based on fluorescence quenching of the oxygen-sensitive ruthenium complex, [Ru(II)-tris(4,7-diphenyl-1,10-phenanthroline]2+, which has been immobilized in a porous silica sol-gel-derived film, is reported. Ormosil sensing films were fabricated using modified silica precursors such as methyltriethoxysilane (MTEOS) and ethyltriethoxysilane (ETEOS) and were dip-coated onto planar glass substrates. Tailoring of the films for dissolved oxygen (DO) sensing is described whereby sensor response is optimized by maximizing film hydrophobicity by the use of the modified precursors. Sensor performance parameters such as limit of detection and sensor resolution are reported. Issues such as dye leaching and photobleaching are discussed. Progress towards a commercial instrument is reported.     

The use of α-(aryl)-4-morpholineacetonitriles (masked acyl anion equivalents) in 1,4-additions to α,β-unsaturated esters and nitriles. A versatile synthetic route to 6-aryl-3(2H) pyridazinones

The use of α-(substituted-phenyl)-4-morpholineacetonitriles in 1,4-additions to ethyl acrylate, ethyl crotonate, methyl α-methylacrylate, acrylonitrile, methylacrylonitrile, crotononitrile and cinnamonitrile was studied. A convenient route to 6-aryl-4,5-dihydro-3(2H) pyridazinones from aryl aldehydes and heterocyclic aldehydes was developed.