Abstract
This is the second of a two-part series on the use of immunochemical and biosensor methods for occupational and environmental monitoring. In Part I (Introduction to Immunoassays), a general overview of the immunology and types of immunoassays was discussed. The major types of enzyme-linked immunosorbent assays (ELISAs), radioimmunoassays (RIA), and lateral flow techniques were described. In the present column, how data are reduced from immunoassays is addressed and some state-of-the-art immunobiosensors are introduced. The advantages of immunoassays and immunobiosensors such as high specificity, portability, small required sample volumes, high sample throughput with simultaneous analysis of multiple samples, reduced sample preparation, reduction in the use of chemicals and production of waste, ease of automation and, in some cases, better accuracy, precision and sensitivity(5,30,34) than traditional chemical/instrumental methods (CIM) far outweigh their limitations. Comparison of ELISA and CIM (usually GC/MS) has shown linear slopes of essentially unity for numerous low molecular weight analytes (triazine herbicides, chlorpyrifos metabolite, dioxins, etc). Recent and future developments in the development of antibody mimics and other receptors, molecular imprinting, microarrays, improved detection systems, immunoaffinity sample preparations, multiplexed immunoassays, and sensors for unattended and real-time analysis will make the use of bioanalytical immunoassays even more attractive. Bioanalytical immunoassay methods are not a panacea, but they should be considered when they can serve as adjuncts to CIM due to their advantages. Yet, current immunoassays, because they use the products of biological systems, are subject to biological variability, sometimes leading to antibody cross-reactivity and other salient binding peculiarities.(1)