Analysis of 2,4-Dichlorophenoxyacetic Acid in Body Fluids of Exposed Subjects Using Radioimmunoassay

The development of a radioimmunological method (radioimmunoassay, RIA) for the determination of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) in human body fluids such as blood serum and urine is described. It comprises three major parts. The first part deals with the generation of a polyclonal anti-2,4-D antiserum in rabbits. This includes the preparation, purification, and characterization of 2,4-D-protein conjugates (immunogens), immunization of rabbits, and evaluation of antiserum quality. A guide is presented that with high probability will lead to useful antibodies. The second part outlines the synthesis and purification of the tracer (i.e., a tritiated 2,4-D with high specific activity) that is selectively labeled in the 6-position of the aromatic moiety. The third part describes carrying out the RIA, setting up the calibration curve, cross-reactivity testing, and evaluation of matrix interferences.