Prefluorescent nitroxide probe for the highly sensitive determination of peroxyl and other radical oxidants.
Fluorescamine derivatized 3-amino-2,2,5,5,-tetramethyl-1-pyrrolidinyloxy (I) is shown to undergo an irreversible reaction with peroxyl radicals and other radical oxidants to generate a more highly fluorescent diamagnetic product (II) and thus can be used as a highly sensitive and versatile probe to determine oxidant production optically, either by monitoring the changes in fluorescence intensity, by HPLC analysis with fluorescence detection, or by a combination of both approaches. By changing the [O2]/[I] ratio, we show that peroxyl radicals can be detected and quantified preferentially in the presence of other radical oxidants. Detection of photochemically produced peroxyl radicals is achieved by employing 3-amino-2,2,5,5,-tetramethyl-1-pyrrolidinyloxy (3-ap) alone, followed by derivatization with fluorescamine. With employment of HPLC analysis, the detection limit of II at a S/N of 2 is approximately 3 nM for a 125 microL injection. Preliminary applications include the detection of peroxyl radicals generated thermally in soybean phosphatidylcholine liposomes and produced photochemically in tap water.
Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA.
Min
M
Jia
Yu
Y
Tang
Yiu-Fai
YF
Lam
Sarah A
SA
Green
Neil V
NV
Blough
D002851:Chromatography, High Pressure Liquid; D003497:Cyclic N-Oxides / Q000737:chemistry*; D005450:Fluorescamine / Q000737:chemistry*; D007202:Indicators and Reagents / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry; D016877:Oxidants / Q000032:analysis* / Q000737:chemistry; D010545:Peroxides / Q000032:analysis* / Q000737:chemistry
C545613:3-amino-2,2,5,5,-tetramethyl-1-pyrrolidinyloxy; D003497:Cyclic N-Oxides; D007202:Indicators and Reagents; D008081:Liposomes; D016877:Oxidants; D010545:Peroxides; C049375:perhydroxyl radical; D005450:Fluorescamine