Potential Application of Gold Nanospheres as a Surface Plasmon Resonance Based Sensor for In-Situ Detection of Residual Fungicides

Abstract

It is essential to develop a simple and sensitive method to rapidly detect residual fungicides in agricultural products to protect human health. So far, little studies have been reported on potential application of gold nanospheres (AuNSps) as a surface plasmon resonance based sensor for in-situ detection of residual fungicides. Therefore, in this study, we investigated the potential application of AuNSps as a surface plasmon resonance based sensor for in-situ detection of fungicides. AuNSps were successfully synthesized via a seed-mediated method with some modifications. Firstly, gold nanoseeds were made during the reduction of chloroauric acid by trisodium citrate dihydrate (TSC). Then, AuNSps were grown from the seeds by using HAuCl 4 , TSC and EDTA. AuNSps were subsequently dropped on a glass substrate before covered by thiophanate methyl, a broad-spectrum systemic fungicide. The AuNSps coated glass substrate was subsequently dried in the air for further surface-enhanced Raman spectroscopy (SERS) measurements. Optical properties, shape and size of AuNSps were confirmed by UV-vis spectroscopy, XRD, SEM-EDX and TEM. The results showed that AuNSps were successfully synthesized with the size of 53 nm, and their resonance peak was located at 560 nm. The Raman signal intensity of thiophanate methyl covered on AuNSps is higher than that without AuNSps, indicating SERS effects of AuNSps deposited glass substrate.

Surface Plasmon Resonance (SPR)-Based Biosensors as Instruments with High Versatility and Sensitivity

“…In the works [4,5], SPR-based assays were employed for pathogen detection and monitoring the traces of fungicide in samples. These works highlighted the potential of SPR-based approaches in agricultural sciences.…”

“…On the other hand, not only early diagnostic of fungal diseases but also the monitoring of residual fungicides in agricultural products is important for agricultural and food sciences. A SPR-based assay suggested in the work [5] helps to detect residual fungicide thiophanate methyl in samples. In this work, home-made gold nanospheres were employed to enhance Raman signal for the detection of residual thiophanate methyl in samples.…”