A rapid and simple chemical method for the preparation of Ag colloids for surface-enhanced Raman spectroscopy using the Ag mirror reaction

Abstract

Colloidal silver (Ag) nanoparticles (AgNP) have been widely used for surface-enhanced Raman spectroscopy (SERS) applications. We report a simple, rapid and effective method to prepare AgNP colloids for SERS using the classic organic chemistry Ag mirror reaction with Tollens’ reagent. The AgNP colloid prepared with this process was characterized using SEM, and the reaction conditions further optimized using SERS measurements. It was found that Ag mirror reaction conditions that included 20 mM AgNO3, 5 min reaction time, and 0.5 M glucose produced AgNP colloids with an average size of 319.1 nm (s.d ±128.1). These AgNP colloids exhibited a significant SERS response when adenine was used as the reporter molecule. The usefulness of these new AgNP colloids was demonstrated by detecting the nucleotides adenosine 5′-monophosphate (AMP), guanosine 5′-monophosphate (GMP), cytidine 5′-monophosphate (CMP), and uridine 5′-monophosphate (UMP). A detection limit of 500 nM for AMP was achieved with the as-prepared AgNP colloid. The bacterium Mycoplasma pneumoniae was also easily detected in laboratory culture with these SERS substrates. These findings attest to the applicability of this AgNP colloid for the sensitive and specific detection of both small biomolecules and microorganisms.

Silver Nanocube-Decorated PVDF Membranes for SERS Substrates

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Raman enhancement effect of different silver nanoparticles on salbutamol

“…Surface-enhanced Raman spectroscopy (SERS) is a novel analytical technique for trace contaminant determination which was realized by the enhanced local electromagnetic field near the nanostructured noble metal surfaces ( Bi et al., 2022 ; Panneerselvam et al., 2018 ). SERS technology can enhance the Raman signal intensity of target molecules by 10 4 –10 6 times ( Lam et al., 2020 ).…”

An experimental guide to in operando electrochemical Raman spectroscopy

“…4 SEM images of copper electrode surfaces before and after ORC different performances of SERS substrates, as the resonance of the laser with the surface plasmon requires a specific nanoparticle size for maximal enhancement. For chemical nanoparticle (NP) synthesis, the size distribution and, therefore, the Raman signal enhancement is easier to adjust and controllable by temperature and reaction time [59]. However, potentially utilized reducing agents and tensides may cause contamination of the Raman spectra with undesired remaining chemicals [53].…”