Abstract: A methamidophos derivative was synthesized by combining O,S-dimethylthiophosphoryl chloride with β-alanine. The productions were identified through TLC and 1HNMR.The derivative was conjugated to bovine serum albumin and ovalbumin by the active ester method and the mixed anhydride method, respectively. The productions were named MZB and MGO, and were identified through ultraviolet spectrum (UV). A spectrophotometric method using 2,4,6-trinitrobenzene sulfonic acid (TNBS) was performed to estimate hapten to carrier protein ratio. The results came to 16:1 and 9:1 for MZB and MGO respectively. Balb/C mice were immunized with MZB and competitive indirect enzyme-linked immunosorbent assay (ELISA) indicates the existence of specific antibodies in the antisera. The titer of antisera is 51:200. This had further verified the success of synthesis. This study lays the groundwork for further research of immunoassay to methamidophos.

Key words: methamidophos, derivation, artificial antigen, antiserum, immunoassay