Nanogold Resonance Rayleigh Scattering Method for Trace (NO_2)~- based on P-Aminobenzene Sulfonic Acid-A-Naphthylamine Colored Reaction

摘要

In acidic condition, (NO_2)~- combined with p-aminobenzene sulfonic acid by diazotization, and then reacted with α-naphthylamine to form purple azo dye. The resonance Rayleigh scattering (RRS) signal of the color system was detected by nanogold probe. Under the chosen conditions, the decreased RRS intensity △I (△I= I_b - I) at 500 nm was linear to the (NO_2)~- concentration in the range of 7.0×10~(-2)-42.0μmol/L, with a regression equation of △I=6.72 C - 6.93, a correlation coefficient of 0.9982 and a detection limit of 2.6×10~(-4) mol/L (NO_2)~-.