Determination of trace hydroxyl radicals by flow injection spectrofluorometry and its analytical application.
On the basis of the fluorescence increase of the reaction of ninhydrin with hydroxyl radicals, a new method for the determination of trace amounts of hydroxyl radicals by flow injection spectrofluorometry is presented. The introduction of flow injection analysis brought better reproducibility and avoided the effect of oxygen and other substances in the environment on the reaction of ninhydrin with hydroxyl radicals. Under optimum experimental conditions, the hydroxylated product of ninhydrin had excitation and emission maxima at 300 and 406 nm, respectively. The linear range was 2.60 x 10(-7) to 4.00 x 10(-5) M, and the limit of detection was 7.91 x 10(-8) M. A high analysis rate of 22 samples per hour was obtained. The proposed method has been applied successfully to the determination of scavenging effects of thiourea and vitamin C on hydroxyl radicals as well as to the evaluation of antioxidant capacities of some natural food.
Gao
Jing Jing
JJ
College of Chemistry, Chemical Engineering and Materials Science, Normal University, Jinan 250014, China.
Xu
Ke Hua
KH
Hu
Ji Xi
JX
Huang
Hui
H
Tang
Bo
B
D003035:Cobalt; D017022:Flow Injection Analysis; D006863:Hydrogen-Ion Concentration; D017665:Hydroxyl Radical / Q000032:analysis*; D007202:Indicators and Reagents; D009555:Ninhydrin; D015203:Reproducibility of Results; D013050:Spectrometry, Fluorescence
D007202:Indicators and Reagents; D017665:Hydroxyl Radical; D003035:Cobalt; D009555:Ninhydrin