Silver nanoparticles for detection of methimazole by surface-enhanced Raman spectroscopy

An efficient method was developed for quantitative detection of methimazole using surface enhanced Raman spectroscopy (SERS). Silver nanoparticles (AgNPs) were prepared by a reduction method and designed as SERS substrates for the detection of methimazole, which is of medicinal importance. The morphology and the structure of the nanoparticles were characterized using a transmission electron microscope, a UV–vis spectroscopy, a Fourier transformed infrared spectroscopy and a Raman spectroscopy. The average size of the AgNPs was 60 nm. The UV–vis spectrum showed a characteristic maximum absorbance at around 420 nm for AgNPs. The adsorption behavior of methimazole on the AgNPs substrates was investigated by SERS and density functional theory (DFT) calculations. SERS experimental and theoretical results imply that a chemical interaction is considered between the NPs and methimazole. SERS experiments indicated an enhancement in the bands, which was utilized to develop a linear correlation between the methimazole concentrations and SERS signal intensity.