Shell Thickness-Dependent Raman Enhancement for Rapid Identification and Detection of Pesticide Residues at Fruit Peels

Abstract

Here, we report the shell thickness-dependent Raman enhancement of silver-coated gold nanoparticles (Au@Ag NPs) for the identification and detection of pesticide residues at various fruit peels. The Raman enhancement of Au@Ag NPs to a large family of sulfur-containing pesticides is ~2 orders of magnitude stronger than those of bare Au and Ag NPs, and there is a strong dependence of the Raman enhancement on the Ag shell thickness. It has been shown for the first time that the huge Raman enhancement is contributed by individual Au@Ag NPs rather than aggregated Au@Ag NPs with "hot spots" among the neighboring NPs. Therefore, the Au@Ag NPs with excellent individual-particle enhancement can be exploited as stand-alone-particle Raman amplifiers for the surface identification and detection of pesticide residues at various peels of fruits, such as apple, grape, mango, pear, and peach. By casting the particle sensors onto fruit peels, several types of pesticide residues (e.g., thiocarbamate and organophosphorous compounds) have been reliably/rapidly detected, for example, 1.5 nanograms of thiram per square centimeter at apple peel under the current unoptimized condition. The surface-lifting spectroscopic technique offers great practical potentials for the on-site assessment and identification of pesticide residues in agricultural products.

Combined use of vancomycin-modified Ag-coated magnetic nanoparticles and secondary enhanced nanoparticles for rapid surface-enhanced Raman scattering detection of bacteria

“…53 Moreover, the Au@Ag NPs exhibit better uniformity to produce stable and producible SERS signals than Ag NPs. 54 Considering these prominent advantages, we chose Au@Ag NPs as the secondary enhanced particles to further enhance the Raman signal of bacteria and improve the detection sensitivity in this work.…”

Fundamentals and applications of SERS-based bioanalytical sensing

“…They can readily be found on the surface of fresh fruits and vegetables. A SERS measurement on fruit can nondestructively detect various pesticides [174,188,189], making a good candidate for a high throughput assay. Quantification is possible under controlled conditions [190].…”

Detection of environmentally hazardous pesticide in fruit and vegetable samples using gold nanoparticles

“…In recently, ELISA has been used to detection of pesticides in fruits and vegetables, and shows great assure as a sensitive and rapid detection method (Fan, Lai, Rasco, & Huang, 2014;Fan, Lai, Rasco, & Huang, 2015;Liu et al, 2012Liu et al, , 2013. The one of the hottest areas is DIA and ELISA application in detection of a pesticide in the skins of fruits and vegetables.…”