Environmental Chemistry: The Immunoassay Option

Abstract Scientific awareness and public concern about the state of our environment have led to unprecedented demands on analytical laboratories. There is now much interest in strategies that will help to lower costs and improve efficiency. Immunoassay (IA) techniques, which are widely used in clinical chemistry, could play a key role in the laboratory of the future. IA screening techniques for the detection of a broad variety of pollutants, including pesticides and industrial contaminants, are reviewed. IAs are best suited to the analysis of large sets of samples. A majority of the methods are sufficiently sensitive and selective for environmental applications. Some approaches that might help improve the sensitivity of IAs so that ultra-trace analytes can be detected are considered. Analytes can usually be detected in water samples with little or no sample preparation. In many cases, an extraction step, which is sometimes followed by a simple clean-up step, suffices for solid matrices. Hydrophobic analytes, such as the polychlorinated dibenzo-p-dioxins, are the exception. Recent advances in the validation of environmental IAs, which should improve the confidence of the unfamiliar analyst, are reviewed. IA kits are available for analysts without the resources to develop their own assays. Some interesting trends that are reviewed include the use of immunosensors for the direct detection of contaminants, the use of immunoaffinity chromatography for the one-step purification of analytes, and the environmental application of electrochemical and flow injection immunoassays. IAs have the potential to boost productivity and release costly instruments for use in the quantification of positive samples.