Surface-enhanced Raman scattering (SERS) from low-cost silver nanoparticle-decorated cicada wing substrates for rapid detection of difenoconazole in potato

SERS detection of triazole pesticide residues on vegetables and fruits using Au decahedral nanoparticles

Triazole pesticides are widely used in modern agricultural practices to improve agricultural production quality. Simultaneously, unreasonable and standardized use of triazole pesticides could induce a series of potential diseases of humans. Surface-enhanced Raman spectroscopy has attracted enormous research attention because of its label-free and fingerprint detection capability to noninvasively trace extremely low concentration analytes. To the best of our knowledge, there is a lack of systematic comparison regarding the Raman spectral information of triazole pesticides in existing literatures. In this work, we successfully captured the characteristic peaks of six different triazole pesticides individually and simultaneously using Au decahedral nanoparticles. The proposed method exhibited remarkable detection sensitivity, a wide dynamic range, and the capability for in-situ detection of multiple pesticide residues on bean, apple, and vegetable surfaces with satisfactory recovery rates. Therefore, our proposed SERS platform have great applications in agricultural products safety, environmental monitoring and other fields.

A new and highly efficient CuMOF-based nanoenzyme and its application to the aptamer SERS/FL/RRS/Abs quadruple-mode analysis of ultratrace malachite green

Malachite green (MG) is highly toxic, persistent, and carcinogenic, and its widespread use is a danger to the ecosystem and a threat to public health and food safety, making it necessary to develop new sensitive multimode molecular spectroscopy methods. In this work, a new copper-based nanomaterial (CuNM) was prepared by a high-temperature roasting using a copper metal-organic framework (CuMOF) as precursor. The as-prepared CuNM was characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy, transmission electron microscopy (TEM), and BET surface area analysis. CuNM was found to catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by H2O2 to produce the oxidation product TMBOX; however, subsequently, the MG aptamer (Apt) could be adsorbed on the CuNM surface by intermolecular interaction, which would inhibit the catalytic performance. After the addition of MG to be tested, the CuNM previously adsorbed by the Apt was transformed into its free state, thus restoring its catalytic activity. This new nanocatalytic indicator reaction could be monitored by surface-enhanced Raman scattering (SERS)/resonance Rayleigh scattering (RRS)/fluorescence (FL)/absorption (Abs) quadruple-mode methods. The SERS determination range was 0.004-0.4 nmol L-1 MG, with a limit of detection of 0.0032 nM. In this way, a rapid, stable, and sensitive method for the determination of MG residues in the environment was established.