Green and Sustainable Self-Cleaning Flexible SERS Base: Utilized for Cyclic-Detection of Residues on Apple Surface

Abstract

Rapid and non-destructive quantitative analysis of residues on the surface of fruits and vegetables has always been a requirement when applying safety monitoring. This research prepared a self-assembled Au@Ag NRs self-cleaning flexible SERS substrate for the detection of methyl parathion (MP) on apple surface. The flexible substrate consists of two kinds of high polymer, namely PVDF and PVP to support the 3D frame via the electrospinning process. Further the substrate was embedded with TiO2 to provide a way for photodegradation of the target material after collection. The results showed that the self-cleaning flexible SERS substrate achieved a LOD response to the MP-contaminated apple surface at levels as low as 0.037 ng/cm2. The substrate successfully photodegraded MP under UV light and the RSD of five cycles-detection was 5.61%. In addition, the recoveries of the other two pesticides (thiram (TMTD) and chlorpyrifos (CPF)) on apple surface were 83.10% - 112.47%, respectively. These results indicated that the self-cleaning flexible SERS substrate provides a rapid, non-destructive and reproducible method for in-situ analysis of residues on fruit and vegetable surfaces.

Keywords: self-cleaning, photodegradation, Au@Ag NRs, Methyl parathion, SERS