An immunoassay for TEQ screening of dioxin/furan samples: Current status of assay and applications development

A simple and easy to use system has been developed for rapid screening of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) in a variety of situations. The system uses a competitive inhibition nzyme mmuno ssay (EIA) based on a previously described mouse monoclonal antibody which is specific for 2,3,7,8-TCDD and related congeners. Two formats have been developed, a rapid tube test and a microplate test. Respective sensitivities are 100 pg/tube and 25 pg/well of 2,3,7,8-TCDD. Congener specificity of the tube test roughly correlates with I-TEF. The concept of TEQ screening is validated by comparing TEQ values for a set of soil samples to the EIA responses predicted for those samples. Actual analysis of crude extracts of some of the same soils indicated some clean-up is required to remove interferences. Rapid extraction and sample clean-up methods for soil and other matrices are being developed. Potential implementation of the EIA in a fixed lab is discussed. The EIA system offers significant improvements in speed, sample throughput, and cost compared to GC-MS. This system should be useful for screening environmental samples in many situations.