title: Multicommutated flow-through optosensors implemented with photochemically induced fluorescence: determination of flufenamic acid.
abstract: This article describes a multicommutated flow injection-solid phase spectroscopy system implemented with photochemically induced fluorescence for the determination of flufenamic acid (FFA). A strongly fluorescent photoproduct is generated when FFA is irradiated online under UV light in a strong sulfuric medium. The photoproduct generated is retained on C(18) silica gel (which fills the detection area of the flow cell) and directly monitored on the active solid support at 258/442 nm (lambda(ex)/lambda(em)). After maximum signal recording, the sensing zone is regenerated by eluting the retained photoproduct with an appropriate H(2)SO(4)/MeOH solution. The sensor, completely automated, is based on the use of three-way solenoid valves conveniently operated by a homemade multicommutation software written in Java language. The system is calibrated at 10 and 60s for sampling time, showing detection limits of 1.28 x 10(-9) and 5.33 x 10(-10) molL(-1) and sampling rates of 38 and 28 h(-1), respectively, with relative standard deviations of 0.9 and 1.2%. The applicability of the method is demonstrated for the determination of FFA in human serum, human urine, and a pharmaceutical preparation without any pre-treatment. Good recovery levels were achieved between 90.5 and 103.7%.
authors.affiliation: Department of Physical and Analytical Chemistry, Faculty of Experimental Sciences, University of Jaén, E-23071 Jaén, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: López-Flores
authors.forename: María L
authors.initials: ML
authors.lastname: Fernández-De Córdova
authors.forename: Antonio
authors.initials: A
authors.lastname: Molina-Díaz
mesh_terms: D000893:Anti-Inflammatory Agents / Q000032:analysis* / Q000097:blood / Q000652:urine; D017022:Flow Injection Analysis / Q000379:methods*; D005439:Flufenamic Acid / Q000032:analysis* / Q000097:blood / Q000652:urine; D005453:Fluorescence; D006801:Humans; D055095:Optics and Photonics; D013050:Spectrometry, Fluorescence / Q000379:methods*; D014466:Ultraviolet Rays
chemical_list: D000893:Anti-Inflammatory Agents; D005439:Flufenamic Acid