title: Modeling of fiber-optic fluorescence probes for strongly absorbing samples.
abstract: The dynamic range of fiber-optic fluorescent probes such as single fibers and fiber bundles is calculated for strongly absorbing samples, such as process liquids, foodstuffs, and lubricants. The model assumes an excitation beam profile based on a Lambertian light source and uses analytical forms of the collection efficiency, followed by an Abel transformation and numerical integration. It is found that the effect of primary absorption of the excitation light and secondary absorption of the fluorescence is profound. For fiber bundles and bifurcated fiber probes, the upper accessible concentration limit is roughly given by the absorption length of the primary and secondary absorption. Fluorescence detectors that are placed at right angles to the excitation beam axis or collinear to the beam axis are equally strongly affected by secondary absorption. A probe in which the same fiber is used for excitation and for collection of the fluorescence emerges as the fiber probe with the largest accessible concentration range.
authors.affiliation: innoFSPEC, Institute for Chemistry, Physical Chemistry, University of Potsdam, Golm, Germany.
authors.forename: Dorit
authors.initials: D
authors.lastname: Munzke
authors.forename: John
authors.initials: J
authors.lastname: Saunders
authors.forename: Hengameh
authors.initials: H
authors.lastname: Omrani
authors.forename: Oliver
authors.initials: O
authors.lastname: Reich
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Loock
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D004867:Equipment Design; D005336:Fiber Optic Technology / Q000295:instrumentation / Q000379:methods*; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry*; D008027:Light; D008962:Models, Theoretical; D055100:Optical Fibers
chemical_list: D005456:Fluorescent Dyes