Pyridine vapors detection by an optical fibre sensor

An optical fibre sensor has been implemented towards pyridine vapors detection;to achieve this, a novel vapochromic material has been used, which, in solid state, suffers achange in colour from blue to pink-white in presence of pyridine vapours. This complex isadded to a solution of PVC (Poly Vinyl Chloride), TBP (Tributylphosphate) andtetrahydrofuran (THF), forming a plasticized matrix; by dip coating technique, the sensingmaterial is fixed onto a cleaved ended optical fibre. The fabrication process was optimizedin terms of number of dips and dipping speed, evaluating the final devices by dynamicrange. Employing a reflection set up, the absorbance spectra and changes in the reflectedoptical power of the sensors were registered to determine their response. A linear relationbetween optical power versus vapor concentration was obtained, with a detection limit of 1ppm (v/v).Financial support from the Spanish Comisión Interministerial de Ciencia y Tecnología within projects TEC2006-12170/MIC, TEC2004-05936-C02-01/MIC, BQU2001-3221, CTQ2005-09023 and Project of Excellence RNM666 de la Junta de Andalucía, is acknowledged