A sensitive resonance Rayleigh light scattering method for alpinetin using gold nanorods probes

A sensitive resonance Rayleigh light scattering (RLS) assay for alpinetin was developed based on alpinetin-modified gold nanorods (AuNRs). Alpinetin could interact with AuNRs and formed a new assembly by electrostatic attraction. In pH7.4 Tris-HCl buffer solution, the assembly of alpinetin-AuNRs showed a sensitive RLS signal. Under optimum conditions, the magnitude of enhanced RLS intensity (I-RLS) was proportional to the concentration of alpinetin over the range 0.027-3.24gml(-1), with a detection limit of 1.79ngml(-1) (by 3 sigma). The developed RLS method was successfully applied to the detection of alpinetin in real or synthesized samples. Alpinetin recoveries were 90.4-108.7% with an RSD of 0.82-2.9% (n=5) for Alpinia katsumadai samples, and 95.1-103.7% with an RSD of 0.28-3.9% (n=5) for synthesized samples. The results showed that this new approach was convenient, reliable and sensitive.