Silver nanoparticles modified with MoS₂ and β-cyclodextrin as SERS substrate for rapid determination of cysteamine...

An efficient Surface-enhanced Raman scattering (SERS) method for the detection of cysteamine hydrochloride (CSH) was developed by synthesizing a composite substrate comprising silver nanoparticles (AgNPs) functionalized with MoS₂ and β-cyclodextrin (β-CD). The enhanced Raman signals of CSH by β-CD/MoS₂/AgNPs substrate were the contribution of electromagnetic enhancement (EM) as well as chemical enhancement (CM), and the enhancement factor (EF) can reach up to 3.11 × 10⁶ (peak at 633 cm^-1). Various instrumental techniques were used to characterize the substrate, such as X-ray diffraction (XRD), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) and ultraviolet visible (UV-vis). The binding of β-CD/MoS₂/AgNPs and CSH was confirmed by UV-vis and Fourier transform infrared (FT-IR). The optimal experimental conditions were determined by single factor experiments as well as response surface model. The influences of different metal ions and analogous drugs on the detection of CSH were investigated. Under optimum conditions, a good linear correlation (R = 0.9997) was established for CSH in the range of 10.00-1000.00 nmol/L, and the limit of detection (LOD) was as low as 0.78 nmol/L (S/N = 3). The contents of CSH in meat samples were detected. The recovery was 96.6-103.1 %, and the relative standard deviation (RSD) of the measurement was 0.7-3.9 % (n = 7).