Synthesis of the Antigens for 2,4-D Type and Development of Its Specific Polyclonal Antibody

2,4- DB, 2,4-D, as two haptens, were conjugated to bovine serum albumin ( BSA) and ovalbumin ( OVA) with improved EDC method, two immunogens of 2,4-DB-BSA, 2,4-D-BSA and two coating antigens of 2,4-DB-OVA, 2,4-D-OVA were obtained. The charac-teristics in ultraviolet absorption spectrum of immunogen possessed those of both carrier protein and haptens, the location of the absorption peak was at 282 nm, same as that of happten, 2,4-D.The reaction ratios of 2,4-DB-BSA and 2,4-D-BSA were 1∶24 and 1∶20 respectively. Those of 2,4-D-OVA and 2,4- DB-OVA, were 1∶10 and 1∶8. The specific polyclonal antibody for 2,4-D were obtained by immunizing New Zealand male white rabbits with the two antigens. Two rabbits PBD1 and PBD2 were immunized with 2,4- DB- BSA, produced high titers of polyclonal antibody( antiserums) as follows, 1∶102 400 and 1∶51 200 respectively. The PBD1 polyclonal antibody was selected to next study. Work concentration of antigens was 3 μg·mL-1, the PBD1 polyclonal antibody was 1∶12 800. The polyclonal antibody to 2,4- D, 2,4- D butyl ester had high sensibility. The midmost inhibitory concentration( I50) and the detection limit( I20) of 2,4-D were 179.8 ng·mL-1 and 1.09 ng· mL-1, and those of 2,4-D butyl ester were 3 010.0 ng·mL-1 and 1.53 ng·mL-1. The peculiar cross- reactivity of the polyclonal antibody against 2,4-D analogous compounds were also tested, the sensibility to 2,4-DB was highest, then 2,4-D, 2,4-D butyl ester, and 2,4-D isopropyl es-ter, but the sensibilitytoMCPA, 2,4,5-T, Dichlorprop were lower.