Hydroquinone-Based Fabrication of Gold Nanorods with a High Aspect Ratio and LSPR Greater than 850 nm to Be Used as a Surface Plasmon Resonance Platform for Rapid Detection of Thiophanate Methyl

Abstract

The use of gold nanorods (AuNRs) as surface-enhanced Raman scattering (SERS) substrates has gained much attraction due to their remarkably aspect-ratio-dependent plasmonic properties. In this report, we described the development of AuNRs with a high aspect ratio and longitudinal surface plasmon resonance (LSPR) >850 nm through a hydroquinone-based fabrication with minor modifications. The synthesis started with the reduction of chloroauric acid (HAuCl4) by sodium borohydride (NaBH4) to make gold nanoseeds from which AuNRs were grown with the aid of silver nitrate (AgNO3), HAuCl4, cetyltrimethylammonium bromide (CTAB), and hydroquinone (HQ). Scanning electron microscopy coupled with energy-dispersive X-ray (SEM-EDX), Transmission electron microscope (TEM), X-ray diffraction (XRD) and Ultra-violet-Visible spectroscopy (UV-Vis) were performed to study the shape, size, and structural and optical properties of AuNRs, respectively. The results showed that AuNRs with high aspect ratios (AR > 3) were single crystals with a heterogenous size distribution, and that the growth of Au nanoseeds into AuNRs took place along the [001] direction. AuNRs exhibited two plasmon resonance peaks at 520 nm and 903 nm, while gold nanoseeds had only a plasmon resonance peak at 521 nm. The as-synthesized AuNRs also showed SERS effects for thiophanate methyl, a broad-spectrum fungicide, with the limit of detection down to 5 mg/L of the fungicide. AuNR-coated glass can serve as a SERS-based sensing platform for rapid detection of thiophanate methyl with high sensitivity and reproducibility.

Poly(L-DOPA)-mediated bimetallic core−shell nanostructures of gold and silver and their employment in SERS, catalytic activity, and cell viability

“…For the synthesis of the AuNRs, we employed a two-step seed-mediated method developed by Nguyen et al [48]. In the seed suspension preparation, the mixture of HAuCl 4 (1 mM, 2.5 ml) and cetyltrimethylammonium bromide (CTAB) (0.5 M, 2 ml) was mixed for 5 min and then freshly-prepared icecold sodium borohydride (0.02 M, 0.15 ml) was added to the mixture under vigorous magnetic stirring at room temperature.…”

Co–Mn Mixed Metal Oxide Nanorods for On-Site Colorimetric Detection of SO32– in Food Samples

“…Since Fe 3 O 4 magnetic nanoparticles were first reported to have peroxidase-like activity, nanoparticles as mimic enzymes had the advantages of low cost, high stability, and adjustable catalytic activity compared to natural enzymes. , An increasing number of nanoparticles had been found as efficient functional catalysts to mimic natural enzymes, such as metal oxides, metal sulfides, nano-based quantum dots, and carbon nanomaterials . Among these nanoenzymes, Co 3 O 4 was considered as a promising nanoenzyme in an oxygen reduction reaction because of its narrow band gap, high stability, low cost, and moderate ability to bind O 2 . , However, pure Co 3 O 4 owing to the magnetic attractive forces and long-range van der Waals forces tended to agglomerate during synthesis, which obviously affected the performance of the catalytic activity. , Previous studies indicated that mixed metal oxides (MMOs) could not only prevent the aggregation of nanoparticles but could also retain activity sites on the surface of nanoparticles. MMOs could establish multimetal structures effectively, in which the synergistic effect existed between the different metal oxides, endowing the nanocomposites with more enhanced catalytic activity than that of the single component.…”