title: Flow injection fluorometric determination of ascorbic acid using perylenebisimide-linked nitroxide.
abstract: A simple and sensitive flow injection fluorometric method for the determination of ascorbic acid is described. Perylenebisimide-linked nitroxide (PBILN) is used as a fluorescent reagent, which permits the selective determination of ascorbic acid. The fluorescence of the perylenebisimide moiety in PBILN is quenched by the nitroxide moiety, which is linked to the perylenebisimide. When a stream of a solution of ascorbic acid is merged with a stream of PBILN, the ascorbic acid reacts with the nitroxide moiety of PBILN to form hydroxylamine, and the fluorescence properties of the perylenebisimide moiety are recovered. As a result, a peak-shaped fluorescence signal is produced, which can be observed by a fluorescence detector located downstream. Under optimized conditions, a good linear relationship between the concentration of ascorbic acid and peak height in the concentration range from 0.5 to 10 μmol L(-1) was found and the detection limit (S/N=3) was 0.28 μmol L(-1). The relative standard deviation for the determination of 4.0 μmol L(-1) ascorbic acid samples was 1.0% (n=5). The proposed method was applied to the determination of ascorbic acid in several soft drink beverages and the analytical results were in good agreement with those obtained using a conventional method.
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan.
authors.forename: Tomoharu
authors.initials: T
authors.lastname: Maki
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Soh
authors.forename: Koji
authors.initials: K
authors.lastname: Nakano
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Imato
mesh_terms: D001205:Ascorbic Acid / Q000032:analysis* / Q000737:chemistry; D001628:Beverages / Q000032:analysis; D002138:Calibration; D003497:Cyclic N-Oxides / Q000737:chemistry*; D017022:Flow Injection Analysis / Q000379:methods*; D005470:Fluorometry / Q000379:methods*; D007202:Indicators and Reagents / Q000737:chemistry; D010569:Perylene / Q000031:analogs & derivatives* / Q000737:chemistry; D013997:Time Factors
chemical_list: D003497:Cyclic N-Oxides; D007202:Indicators and Reagents; D010569:Perylene; D001205:Ascorbic Acid