Development of an Enzyme-Linked Immunosorbent Assay for the α-Cyano Pyrethroids Multiresidue in Tai Lake Water

A general and broad class selective competitive enzyme-linked immunosorbent assay (ELISA) for the detection of the a-cyano pyrethroids was developed. One class specific hapten, the 5-(3-benzylphenyl)-5-cyanopentanoic acid (CPBA-BE), was conjugated with BSA as an immunogen. Polyclonal antibodies, PY-antibodies, were generated. The assay with the most selectivity for the family cc-cyano pyrethroids such as cyphenothrin was further optimized and tested for tolerance to cosolvent, pH, and ionic strength changes. The IC50 values of the optimized immunoassay were 4.58 mu g L-1 for cyphenothrin, 5.62 ug L-1 for fenpropathrin, 7.08 mu g L-1 for deltamethrin, 10.72 mu g L-1 for cypermethrin, 19.95 mu g L-1 for flucythrinate, and 28.18 mu g L-1 for esfenvalerate. The cross-reactivities of cyphenothrin, fenpropathrin, deltamethrin, cypermethrin, flucythrinate, and esfenvalerate were 100%, 81.49%, 64.68%, 42.72%, 22.96%, and 16.25%, respectively. The low detection limit (LDL) of this assay was 0.107 mu g L-1 for cyphenothrin. This method was used for the detection of the alpha-cyano pyrethroids in Tai lake water.