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.
Jia
Min
M
Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA.
Tang
Yu
Y
Lam
Yiu-Fai
YF
Green
Sarah A
SA
Blough
Neil V
NV
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