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Updated: Jun 22, 2026

Chemiluminescence-based Assays for Detection of Nitric Oxide and its Derivatives from Autoxidation and Nitrosated Compounds
Published on: February 16, 2022
Fluorometric determination of nitrite with 2,3-diaminonaphthalene by reverse phase HPLC under alkaline conditions
Yang-Il Fang1, Hisayuki Ohata, Kazuo Honda
1Department of Pharmacology, School of Pharmaceutical Sciences, Showa University, Tokyo, Japan. fang@pharm.showa-u.ac.jp
Introduction:
In this study, a simple and sensitive fluorometric HPLC method was described for the determination of nitrite, an indicator of nitric oxide production in biological samples.
Methods:
Nitrite was reacted with 2,3-diaminonaphthalene (DAN) to form fluorescent 2,3-naphthotriazole (NAT). Because NAT has higher fluorescence intensity at alkaline conditions, a reverse phase HPLC method employing a polymer-based column was applied to separate NAT using an alkaline mobile phase system.
Results:
NAT was well separated from DAN and other fluorescent substances with increased detection sensitivity under alkaline conditions. A linear relationship (r=0.999) between the fluorescence intensity of NAT and the concentration of nitrite was observed in the range from 0 to 800 nM with the detection limit of about 25 nM.
Discussion:
The present HPLC method appears suitable for routine analysis of nitrite in crude biological samples, since the polymer-based column can withstand rigorous cleaning with either acid or base.
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