Quantitatively chemo-fluorometry diagnostic to nitrite ion in ultrasound aqueous medium containing 2,3-diaminonaphthalene

• Fluorometry diagnostic reaction of 2,3-diaminonaphthalene (DAN) was studied, as 1-[H]-naphthotriazole was detected in ultrasound medium.
• DAN became the probing molecule for NO2− ion in ultrasound medium.
• It was possible to detect NO2− concentration by the chemo-fluorometry in ultrasound condition.

When ultrasound (US) was exposed in aqueous solution of 2,3-diaminonaphthalene (DAN) in air atmosphere, fluorescent spectra were measured after different US exposure times. US exposure was carried out at 43, 141 and 500 kHz with constant out-put power of 50 W. It was found that the DAN fluorescent having 410 nm emission maximum was decreased as the US exposure was increased, but, the fluorescent at 505 nm for 1-[H]-naphthotriazole (NTTA) was increased. This exhibited that the DAN fluorophore was converted to NTTA by the US exposure, especially at 141 kHz. The calibration analysis was indicated the DAN framework was changed to triazole ring from DAN and NO2− ion. As a result, the characteristic NTTA fluorescent became probe to NO2− ion in US medium. The chemo-fluorometry of the DAN was original work to be useful detecting to nitric acid ion in US exposure solution.