The application of immunoaffinity chromatography for the analysis of tetrachlorodibenzo-p-dioxin in bovine milk

An immunoaffinity column generated by cross-linking a polyclonal chicken an tibody with CNBr-activated Sepharose 4B was used for isolation of 1,3,7,8-t etrachlorodibenzo-p-dioxin (1,3,7,8-TCDD) from bovine milk. Direct applicat ion of a milk sample, even if diluted 1:50 with 0.05% Triton X-100, interfe red with the binding of 1,3,7,8-TCDD to the column, Pre-immunoaffinity colu mn clean-up using liquid-liquid extraction followed by solid phase extracti on produced excellent retention of 1,3,7,8-TCDD by the column. The TCDD was easily eluted by increasing the Triton X-100 concentration to 0.5%. Althou gh analysis of milk samples requires more stringent clean up than serum sam ples, the immunoaffinity chromatography column procedures provide specific clean-up for these samples.