A New Rapid Method for Detecting Trace Nitrite Using Ultrasound Assistance

Trace-level nitrite detection is essential for environmental monitoring. We have developed a rapid, reagent-minimal method for the detection of trace amounts of nitrite. Our study focused on the spectral characteristics of the fluorescent probe 6-amino-1,3-naphthalenedisulfonic acid (ANDSA). We identified the fluorescence intensity at excitation and emission wavelengths of 278 nm and 465 nm, respectively, as the key indicator of nitrite quantification. This method, utilizing a 278 nm excitation wavelength, achieves high sensitivity for trace levels of nitrite. The incorporation of ultrasound assistance has reduced the detection time to 12 min. Through method optimization, only two reagents, sulfuric acid and potassium bromide, are required to form the ANDSA solution for sensitive nitrite detection. Nitrite addition reduces the fluorescence emission peak of ANDSA. In the nitrite concentration range of 0 to 3.2 µM, a strong exponential relationship exists between ANDSA's fluorescence response and nitrite concentration, conforming to the equation F₀/F = 0.94183 × e^(0.8766 C). The proposed method yields reliable results, with relative standard deviations ranging from 0.4% to 2.5% and recovery rates between 89.87% and 101.97% for real water samples. This method provides a highly sensitive solution for nitrite monitoring.