Rapid and sensitive detection of 2,4-dichlorophenoxyacetic acid residual on fruit surface via SERS-tape sampling

The residual 2,4-dichlorophenoxyacetic acid (2,4-D) in fruits poses a serious threat to human health. The continuous deposition of 2,4-D in the body may cause symptoms such as cancer or Alzheimer's disease, therefore, it is of great significance for the detection of 2,4-D traces on fruits. In this paper, we proposed a simple “paste-collect-test” strategy based on surface-enhanced Raman spectroscopy via tape sampling (SERS-tape sampling). The flexibility and stickiness of commercial tapes were combined with the excellent activity of optimized silver nanoparticles (Ag NPs) for rapid trace detection of pesticides in cherry tomatoes. The first two steps of “paste” and “collect” were completed by the tape to simplify the sampling procedure of the analyte molecules, and the “test” step was accomplished by deposing Ag NPs on the surface of the tape after analyte collection. The whole process was completed in a few minutes. The results showed that the limit of detection (LOD) of 2,4-D in cherry tomatoes was 3.63 × 10⁻¹⁰ M with the SERS-tape sampling approach, which is much lower than the maximum residue limit specified by the European Union (EU). This simple and easy-to-operate method is highly sensitive and could be a promise of 2,4-D for food safety.