Silver nanoparticles modified by β-cyclodextrin and γ-alumina as substrate for quantitative SERS detection of netilmicin

Abstract

Based on silver nanoparticles modified by β-cyclodextrin and γ-alumina (β-CD/γ-Al2O3@AgNPs), a novel and sensitive surface-enhanced Raman spectroscopy (SERS) assay for the determination of netilmicin was established. The synthesized SERS substrate of β-CD/γ-Al2O3@AgNPs was characterized by ultraviolet visible (UV–vis) spectroscopy and transmission electron microscope (TEM), and the interaction between netilmicin and β-CD/γ-Al2O3@AgNPs was also investigated by the above methods as well as Fourier transform infrared (FT-IR). The optimum experimental conditions including the type of media, amounts of β-CD/γ-Al2O3@AgNPs and NaCl and mixing time were found. The enhancement factor (EF) was 1.18 × 107 (peak at 577 cm−1). There was a good linear relationship between the concentration of netilmicin and the SERS intensity with the equation of ISERS = 136.12 c + 47201.80 (c: nmol L−1, r = 0.9975), and the linear range was 10.00–300.00 nmol L−1. The limit of detection (LOD) was 1.85 nmol L−1 (S/N = 3). The effects of some interferences including Cu2+, K+, Zn2+, Ca2+, Na+, Mg2+, glucose, l-tryptophan HSA and kanamycin were studied. This method was used to detect netilmicin in human serum samples with the recovery of 97.96%–103.52% and the RSD of 1.2%–2.1%.