A compound of Formula: OP-Peptide-Linker-CP wherein OP is selected from the group consisting of reactive organophosphorus reagents, nerve agents and pesticides, wherein P is Sp stereoisomer, R p stereoisomer, or mixture thereof; R is alkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, alkylidenyl, substituted alkylidenyl, alkenylidenyl, substituted alkenylidenyl, alkoxy, substituted alkoxy, halo, haloalkyl, hydroxy, hydroxyalkyl, aryl, substituted aryl, heteroaryl, substituted heteroaryl, heterocycle, substituted heterocycle, cycloalkyl, substituted cycloalkyl, amino, substituted amino, alkylamino, acylamino, trifluoromethyl, trifluoromethoxy, cyano, methyl, ethyl, isopropyl, n-propyl, n-butyl, tert-butyl, cyclohexyl, pinacolyl, methoxy, ethoxy, propoxy, or dimethylamino; R' is selected from the group consisting of alkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, alkylidenyl, substituted alkylidenyl, alkenylidenyl, substituted alkenylidenyl, haloalkyl, hydroxyalkyl, aryl, substituted aryl, heteroaryl, substituted heteroaryl, heterocycle, substituted heterocycle, cycloalkyl, substituted cycloalkyl, trifluoromethyl, methyl, ethyl, isopropyl, pinacolyl, and cyclohexyl; X is oxygen, sulfur, selenium or imino; Peptide is a sequence of amino acids containing a serine, threonine or tyrosine to which an OP is attached, wherein a total number of amino acids is between 7 and 41; Linker is an amino acid or other bifunctional reagent capable of covalently linking OP-peptide to a CP; CP is a conjugate protein used to display haptens for antibody generation; and salts thereof. OP is selected from the group consisting of reactive organophosphorus reagents, nerve agents and pesticides, wherein P is Sp stereoisomer, R p stereoisomer, or mixture thereof; R is alkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, alkylidenyl, substituted alkylidenyl, alkenylidenyl, substituted alkenylidenyl, alkoxy, substituted alkoxy, halo, haloalkyl, hydroxy, hydroxyalkyl, aryl, substituted aryl, heteroaryl, substituted heteroaryl, heterocycle, substituted heterocycle, cycloalkyl, substituted cycloalkyl, amino, substituted amino, alkylamino, acylamino, trifluoromethyl, trifluoromethoxy, cyano, methyl, ethyl, isopropyl, n-propyl, n-butyl, tert-butyl, cyclohexyl, pinacolyl, methoxy, ethoxy, propoxy, or dimethylamino; R' is selected from the group consisting of alkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, alkylidenyl, substituted alkylidenyl, alkenylidenyl, substituted alkenylidenyl, haloalkyl, hydroxyalkyl, aryl, substituted aryl, heteroaryl, substituted heteroaryl, heterocycle, substituted heterocycle, cycloalkyl, substituted cycloalkyl, trifluoromethyl, methyl, ethyl, isopropyl, pinacolyl, and cyclohexyl; X is oxygen, sulfur, selenium or imino; Peptide is a sequence of amino acids containing a serine, threonine or tyrosine to which an OP is attached, wherein a total number of amino acids is between 7 and 41; Linker is an amino acid or other bifunctional reagent capable of covalently linking OP-peptide to a CP; CP is a conjugate protein used to display haptens for antibody generation;