Immunoassays differing in selectivities for pyrethroid insecticides have been developed for the detection of type II pyrethroids, including deltamethrin, cypermethrin, and λ-cyhalothrin. Two approaches were employed in hapten synthesis to raise antibodies with different cross- reactions:(1) use of three spacer attachment points to offset different parts of molecules from the points of attachment and (2) use of linkers with and without bulky groups in the ...