Development of an Indirect Competitive Chemiluminescent Enzyme Immunoassay for the Detection of 2,4‐Dichlorophenoxybutyric Acid in Foods

ABSTRACT 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 (IC 20 –IC 80 ) and sensitivity (IC 50 ) 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.