Immunochemical analysis for dioxins } progress and prospects

Recent developments in antibody design and sample preparation have considerably enhanced the use of enzyme immunoassay EIA. as an alternative to the conventional techniques based on gas chromatography and mass spectroscopy for the analysis of the trace organic pollutants polychlorinated dibenzo-p-dioxins PCDDs. and polychlorinated dibenzofurans PCDFs. in source and environmental samples. The EIA-specific sample preparation technique for solid matrices using a compatible extracting solvent coupled with an assay using a more sensitive antibody permits screening of source and environmental samples to be undertaken with minimal sample preparation. EIA has been validated on an increasing range of environmental and source samples as a cost effective I-TEQ screening tool, exploiting the commonly recognised general strengths of immunoassays such as speed, simplicity, low cost and parallel processing of many samples, greatly reducing the number of samples requiring conventional GCMS analysis. Further research and developmental work is required in the areas of sample extraction and extract cleanup to ensure compatibility with the immunoassay from the outset, and to standardise as far as is possible an assay format relevant to the application of interest, covering sample preparation, sample cleanup, quality control, assay procedure and data analysis.