Rapid detection of benzimidazole fungicides by electrostatic self-assembly of MXene@PEI@AgNPs composite SERS substrate combined with chemometrics

Benzimidazole fungicides are widely used in agriculture, and residues in food will threaten public health and safety. In this study, MXene@PEI@AgNPs composites were successfully constructed by electrostatic self-assembly method using polyethyleneimine (PEI) as a linker and used as a surface-enhanced Raman scattering (SERS) active substrate. The material combines the electromagnetic enhancement of silver nanoparticles and the chemical enhancement mechanism of MXene, showing excellent SERS performance. The experimental results show that the SERS substrate has excellent enhancement performance and successfully obtains the characteristic spectra of six target fungicides. After that, it was combined with chemometrics methods, through principal component analysis (PCA), it was found that the SERS spectra of different fungicides showed obvious clustering distribution. The constructed support vector machine (SVM) classification model shows excellent prediction performance, with an accuracy rate of 100 %. In terms of quantitative analysis, the method showed good sensitivity, and the detection recoveries of benzimidazole fungicides in actual samples such as kiwifruit, tomato and citrus were 81.62 % −113.87 %. Finally, in order to verify the reliability of the method, the high performance liquid chromatography (HPLC) method was used for comparative verification. The results showed that the two methods had good consistency.