Ultrasensitive determination of lipid soluble antioxidants in food products using silver nano-tripod SERS substrates

Abstract

Lipid soluble antioxidants can effectively prevent the oxidative deterioration of oils and fat-containing foods. However, long-term consumption of foods containing antioxidants may damage human health. Herein, a highly sensitive surface-enhanced Raman scattering (SERS) method was explored for the detection of antioxidants by constructing multi-hot silver nano-tripod (AgNT) substrates. Finite difference time domain (FDTD) calculation demonstrated that the “hot spots” of AgNT structures are widely spread, which endows the substrate with excellent detection ability. The enhancement factors (EFs) for trans-1,2-bis(4-pyridyl)ethylene (BPE) and rhodamine 6G (R6G) were 1.08 × 109 and 4.46 × 108, respectively. Combined with density functional theory, AgNT substrates achieved rapid detection of four common antioxidants such as butylated hydroxyanisole (BHA), tertiary butylhydroquinone (TBHQ), butylated hydroxytoluene (BHT) and propyl gallate (PG). The limit of detection (LOD) of BHA, TBHQ and PG was 1 mg/L, and the LOD of BHT was 2 mg/L. Moreover, the substrate combined with principal component analysis can effectively identify antioxidants in fried potato chips. This substrate-based SERS method does not require complex sample pretreatments, and can identify and analyze types and contents of antioxidants added in food in a short time (2 min), providing a portable means for food safety control.