Flexible and Transparent SERS Substrates Composed of Au@Ag Nanorod Arrays for In Situ Detection of Pesticide Residues on Fruit and Vegetables

Abstract

Due to the increasing importance of food quality/safety control, there is an imminent need to develop efficient methods for the rapid detection of pesticide residues in agricultural products. Herein, we proposed a simple and rapid detection approach to the in situ detection of residual pesticides on fruit/vegetable using surface-enhanced Raman spectroscopy (SERS). Flexible and transparent SERS substrates were fabricated by transferring Au@Ag core-shell nanorods (Au@Ag NRs) arrays to silicone membranes, with the single-layer Au@Ag NRs arrays prepared by the liquid–liquid interface self-assembly method. The as-prepared SERS sensor showed excellent SERS activity and repeatability, and it could be readily pasted onto the surface of fruit and vegetables for residual pesticide detection. For the inspection of thiram in contaminated strawberries, apples, and mushrooms, the limit of detection (LOD) could reach 2 ng/cm2 with high measurement recovery and reproducibility. In general, this work provides an effective way for the preparation and application of flexible and transparent SERS substrates in food-safety control.

Design, Fabrication, and Applications of SERS Substrates for Food Safety Detection: Review

“…In this section, the SERS substrates applied for food safety that included the pesticide, antibiotic, microorganic, and metal ions are reviewed, respectively. Table 4 shows currently reported SERS substrates for sensing pesticides and their substrates, metal particles, target substances, and performances [151][152][153][154][155][156][157][158]. In the various pesticides, thiram is one of most common pesticides in SERS applications, such as detecting the thiram on the surface of apples [153,156], oranges [154], strawberries [156], mushrooms [156], tea leaves [158], and farm-produces [159].…”

“…Table 4 shows currently reported SERS substrates for sensing pesticides and their substrates, metal particles, target substances, and performances [ 151 , 152 , 153 , 154 , 155 , 156 , 157 , 158 ]. In the various pesticides, thiram is one of most common pesticides in SERS applications, such as detecting the thiram on the surface of apples [ 153 , 156 ], oranges [ 154 ], strawberries [ 156 ], mushrooms [ 156 ], tea leaves [ 158 ], and farm-produces [ 159 ]. Xiao et al fabricated a 3D SERS substrate by reducing the gold NPs on the bacterial cellulose (BC).…”

“…The BC film, coated with the gold NPs, formed a flexible nanocomposite SERS substrate to determine thiram on apple surfaces to the concentration of 0.5 ppm [ 153 ]. Liu et al fabricated Au@Ag core-shell nanorods by the liquid–liquid interface self-assembly method and coated the Au@Ag core-shell nanorods on the silica gel to form the flexible and transparent SERS substrate [ 156 ]. The Au@Ag NRs arrays can detect the thiram on the surface of the strawberries, mushrooms, and apples with LOD of 2 μg/L [ 156 ].…”

Recent Progress in Nanotechnology-Based Approaches for Food Monitoring

“…The flexible and transparent SERS platforms, which are composted of Au@Ag nanorod array, were developed for in situ detection of pesticide residues on fruits and vegetables ( Figure 4 C) [ 177 ]. The monitoring of thiram in contaminated strawberries, apples, and mushrooms reached the limit of detection of 2 ng/cm 2 with high measurement recovery and reproducibility.…”

“…( C ) In situ detection of pesticide residue by flexible and transparent Au@Ag nanorid array. Reprinted with permission [ 177 ], copyright 2022, MDPI.…”