Development and authentication of a rapid competitive ELISA kit for Chlorothalonil residues.

Objective To develop a competitive ELISA test kit for the detection of Chlorothalonil(CTN) and determine its characteristics.Methods A competitive ELISA test kit for the detection of CTN(CTN-Kit) was developed based on a specific CTN monoclonal antibody(mAb).Results The calibration curve of the CTN-Kit was a typical sigmoidal curve,fitting a four parameter logistic equation over the range of 1.03 to 845.46 μg/L of CTN(R 2 =0.9922),with the sensitivity of 2.5 μg/L,IC 50 of 29.44 μg/L and a detection limit of 3.0 g/L.The recoveries for CTN doping of cucumber and tomato were 92.0% and 94.0% respectively.The precision and accuracy of the assay as determined by inter-assay and intra-assay coefficient variation were both below 10%.The CTN-Kit gave a cross-reactivity of 1.7% with quintozene and little or no cross-reactivity towards other compounds.The viability of the CTN-Kit at 4 ℃ was above six months.Conclusion This CTN-Kit has a good sensitivity,accuracy and reproducibility,and is suitable for the detection of CTN in agricultural products.