Gold Nanorod Resonance Rayleigh Scattering-Energy Transfer Spectral Determination of Trace Formaldehyde with 4-Amino-3-Hydrazino-5-Mercap-1,2,4-Triazole

Abstract

In the KOH medium, the as-prepared gold nanorods (AuNR) were aggregated to AuNR aggregates that exhibited strong resonance Rayleigh scattering (RRS) at 440 nm. Formaldehyde reacted with 4-amino-3-hydrazino-5-mercap-1,2,4-triazole (AHMT) to form a purplish red compound 6-mercapto-S-triazole [4,3-b]-S-tetrazole with strong hydrophobic ability that as receptors were closed to the surfaces of AuNR aggregates as donors. When the system was irradiated, the RRS-energy transfer (RRS-ET) takes place, which results in the RRS signal quenching at 440 nm. With the increase of formaldehyde concentration, the formed receptors increased, and the RRS intensity quenched linearly at 440 nm due to the RRS-energy transfer enhancing. The quenched intensity responds linearly with formaldehyde concentration in the range of 0.25–48 μmol/L. Thus, a new AuNR surface plasmon RRS-ET method was developed for the determination of trace formaldehyde, with satisfactory results.