Detection of myclobutanil and tebuconazole in apple using magnetic molecularly imprinted polymer surface-enhanced Raman spectroscopy

Abstract

The main challenge in Raman detection of pesticide residues in agricultural products is matrix interference, which hinders accurate identification of trace compounds in complicated agricultural samples. In this study, a novel surface-enhanced Raman spectroscopy approach based on magnetic molecularly imprinted polymers (MMIP-SERS) was introduced for the rapid analysis of myclobutanil and tebuconazole in apples. The synthesized magnetic molecularly imprinted polymer selectively adsorbed triazole pesticides, effectively eliminating matrix interference in real samples. The saturation adsorption time for MMIPs was only 10 min. In addition, the synthesized colloidal gold served as an excellent substrate for enhancing the specific signals for myclobutanil and tebuconazole. We successfully identified the characteristic peak of tebuconazole at 1089 cm−1, while myclobutanil showed its characteristic peak at 632 cm−1. The series of experiments and recovery tests confirmed the high sensitivity of the developed MMIP-SERS method using colloidal gold as an enhanced substrate for fungicide analysis in apple samples. The linear detection ranges for myclobutanil and tebuconazole in apples were determined to be 0.2–10 mg/kg and 0.5–10 mg/kg, respectively. The limit of detection was 0.09 mg/kg for tebuconazole and 0.05 mg/kg for myclobutanil. This study provides a rapid and simple method for detecting myclobutanil and tebuconazole based on the synergistic effect of the imprinted polymer and SERS with good separation and detection performance.