Search Results (3)

In recent years, the development of surface-enhanced Raman spectroscopy (SERS) substrates has seen significant advancement. In this research, we successfully fabricated cotton swab-based SERS substrates using a facile solution-based method. Our SERS substrates showed not only ultrasensitive detection capability but also impressive long-term stability and multiple recyclability rounds. In particular, we reported a detection limit of 10⁻¹² M RhB and a detectable concentration of thiophanate methyl as low as 10⁻¹⁰ M using our cotton swab-based SERS substrates. The stability of our substrates reached a 12-month mark, and they were recycled as many as five times simply by cleaning them with ozone. Full article

It is both important and required to quickly and accurately detect chemical warfare agents, such as the highly toxic nerve agent sarin. Surface-enhanced Raman scattering (SERS) has received considerable attention due to its rapid results, high sensitivity, non-destructive data acquisition, and unique spectroscopic fingerprint. In this work, we successfully prepared SERS cotton swabs (CSs) for the detection of the sarin simulant agent dimethyl methyl phosphonate (DMMP) by anchoring N1-(3-trimethoxysilylpropyl) diethylenetriamine (ATS)/silver nanoparticle (AgNP) nanocomposites on CSs using ATS as the stabilizer and coupling agent. Simultaneously, the binding mode and reaction mechanics between the AgNP, ATS, and CS were confirmed by XPS. The modified CSs exhibited good uniformity, stability, and adsorption capability for SERS measurements, enabling the adsorption and detection of DMMP residue from an irregular surface via a simple swabbing process, with a detection limit of 1 g/L. The relative standard deviations (RSDs) of RSD₇₁₀ = 5.6% had high reproducibility. In this research, the fabrication method could easily be extended to other cellulose compounds, such as natural fibers and paper. Furthermore, the versatile SERS CSs can be used for the on-site detection of DMMP, particularly in civil and defense applications, to guarantee food security and the health of the population. Full article

As an important sort of dithiocarbamate bactericide, thiram has been widely used for fruits, vegetables and mature crops to control various fungal diseases; however, the thiram residues in the environment pose a serious threat to human health. In this work, silver nanoparticles (AgNPs) were grown in-situ on cotton swab (CS) surfaces, based on the mussel-inspired polydopamine (PDA) molecule and designed as highly sensitive surface-enhanced Raman scattering (SERS) swabs for the conformal rapid detection of bactericide residues. With this strategy, the obtained CS@PDA@AgNPs swabs demonstrated highly sensitive and reproducible Raman signals toward Nile blue A (NBA) probe molecules, and the detection limit was as low as 1.0 × 10⁻¹⁰ M. More critically, these CS@PDA@AgNPs swabs could be served as flexible SERS substrates for the conformal rapid detection of thiram bactericides from various fruit surfaces through a simple swabbing approach. The results showed that the detection limit of thiram residues from pear, grape and peach surfaces was approximately down to the level of 0.12 ng/cm², 0.24 ng/cm² and 0.15 ng/cm² respectively, demonstrating a high sensitivity and excellent reliability toward dithiocarbamate bactericides. Not only could these SERS swabs significantly promote the collection efficiency of thiram residues from irregular shaped matrices, but they could also greatly enhance the analytical sensitivity and reliability, and would have great potential for the on-site detection of residual bactericides in the environment and in bioscience fields. Full article