Enzyme-linked immunosorbent assay and immunochromatographic strip for rapid detection of atrazine in three medicinal herbal roots

Abstract

Objectives: An enzyme-linked immunosorbent assay (ELISA) and colloidal gold-based immunochromatographic (ICG) strip assay will be developed for the rapid and high-throughput detection of atrazine (ATZ) in medicinal herbs. Methods: A monoclonal antibody against ATZ was obtained after the immunization of mice, cell fusion, and hybridoma screening, and the antibody was used to develop direct competitive ELISA (dcELISA) and the ICG strip assay. Results: Both dcELISA and ICG strip methods were established, optimized, and validated for the detection of ATZ in Salviae miltiorrhizae radix et rhizome, Astragali radix, and Isatidis radix. dcELISA had a half-maximum inhibition concentration of 10.56 ng/mL (Salviae miltiorrhizae radix et rhizome), 7.6 ng/mL (Astragali radix), and 8.15 ng/mL (Isatidis radix). The limit of detection (LOD) of the ICG strip assay was 12.5 ng/mL (Salviae miltiorrhizae radix et rhizome), 12.5 ng/mL (Astragali radix), and 6.25 ng/mL (Isatidis radix) in different herb matrices. Due to the recognition characteristics of the monoclonal antibody for the pesticides ATZ, propazine, sebuthylazine, and prometryn, the detection results of real samples by the two immunoassays were confirmed by liquid chromatography–tandem mass spectrometry, which proved the accuracy and reliability of the established methods. Conclusion: The proposed dcELISA and ICG strip methods were suitable for the rapid, convenient, and high-throughput detection of ATZ in these medicinal herbs.