Development of an Indirect Competitive Chemiluminescent Enzyme Immunoassay for the Detection of...

2,4-Dichlorophenoxybutyric acid (2,4-DB) is a selective systemic hormonal herbicide mainly used to control annual and perennial broadleaf weeds in cereal crop fields. If 2,4-DB is used improperly, it will endanger human health and pollute the environment. To establish an efficient indirect competitive chemiluminescent enzyme immunoassay (2,4-DB-ic-CLEIA) for the detection of 2,4-DB, we used anti-2,4-DB monoclonal antibodies as detection antibodies, explored the optimal reaction conditions for 2,4-DB-ic-CLEIA and verified them by gas chromatography-mass spectrometry (GC-MS). The results showed that under the optimal conditions of each detection element, the linear regression equation obtained based on the inhibition rate and the concentration of 2,4-DB was y = -0.2907 x + 0.9921, and the detection range (IC₂₀-IC₈₀) and sensitivity (IC₅₀) were 4.6-530.6 and 49.3 pg/mL, respectively. The spike recovery rate of the food samples was approximately 82.0%-93.7%, and the intra- and inter-assay precision coefficients of variation were both < 9.2%. The 2,4-DB-ic-CLEIA results measured using GC-MS were highly consistent. In summary, the 2,4-DB-ic-CLEIA established in this study has the advantages of accuracy, reliability, high sensitivity and strong specificity and can be used for the residual detection and analysis of 2,4-DB in various foods.