Jarzebinska, RenataKorposh, SergiyJames, Stephen W.Batty, William J.Tatam, Ralph P.Lee, Seung-Woo2014-01-302014-01-302012-07-31Renata Jarzebinska, Sergiy Korposh, Stephen James, William Batty, Ralph Tatam and Seung-Woo Lee, Optical Gas Sensor Fabrication Based on Porphyrin-Anchored Electrostatic Self-Assembly onto Tapered Optical Fibers, Analytical Letters, Volume 45, Issue 10, 2012, Pages 1297-1309.0003-2719http://dx.doi.org/10.1080/00032719.2012.673097http://dspace.lib.cranfield.ac.uk/handle/1826/8215Tapered optical fibers with nano-assembled coatings of thicknesses of order tens of nanometres were used for the detection of ammonia gas. The film coating was composed of alternate layers of tetrakis-(4-sulfophenyl) porphine (TSPP) and poly(allylamine hydrochloride) (PAH), which were deposited using the electrostatic self-assembly process (ESA). Exposure of a PAH/TSPP nano-assembled non-adiabatic tapered optical fiber with a waist diameter of 10µm to ammonia induced significant optical changes in the transmission spectrum of the optical fiber. The fiber optic sensor showed a linear sensitivity to the concentration of ammonia in the range of 10-100ppm, with response and recovery times less than 100 and 240sec, respectively. The 3σ limit of detection (LOD) was estimated to be ca. 2ppm.This is a postprint of an article whose final and definitive form has been published in the Analytical Letters 2012 copyright Taylor & Francis; Analytical Letters is available online at: http://www.tandfonline.com/doi/abs/10.1080/00032719.2012.673097#.UuuBSLS0CW9Article