One-step chemical reaction triggered surface enhanced Raman scattering signal conversion strategy for highly sensitive detection of nitrite

Abstract Facile detection of nitrite is of great importance in environment and food monitoring. This study proposed a one-step chemical reaction induced signal conversion strategy for highly sensitive detection of nitrite using surface enhanced Raman scattering (SERS). SERS detection of nitrite was based on the nitrite-thiol reaction between nitrite and 2-thiobarbituric acid in acidic condition. The generated S-nitrosothiol compound was detected in solution using a portable Raman spectrometer system and homemade gold nanoparticles as enhancing substrates. Under the optimal conditions, intensity of the highest characteristic band of the generated S-nitrosothiol compound at ∼685 cm-1 has a good linear relationship with the concentration of sodium nitrite in the range of 0.5-17 μg/mL (R2=0.9964). The calculated limits of detection and quantification were 0.21 μg/mL and 0.25 μg/mL, respectively. Nitrite in tap water and pickled brine were successfully detected and quantified using the developed SERS method within 30 min. This method offers an exciting opportunity for highly sensitive on-site detection of nitrite. The proposed chemical reaction based SERS signal conversion strategy shed light on SERS study of small molecules with inherently weak Raman signals.