Clean water, its secure delivery to consumers, and protection of resources are among the most important tasks for humans in future. To protect water resources and control water quality, it is necessary to develop fast, sensitive, cost-effective, and easy-to-use analytical systems capable of measuring a variety of small organic pollutants in aqueous samples.
Immunoassays use antibodies as a versatile analytical tool and are nowadays introduced into many different applications. The predominant testformats in the past have been the RIA (radioimmunoassay) and ELISA (enzyme linked immune sorbent assay). Together with the developments in the area of biosensors, the need for automated immunoassays carried out at the heterogeneous phase has lead to the development of new assay formats. Usually, these systems combine the approaches of various immunoassays with Flow Injection Analysis (FIA) systems and different fluorescence or label-free transduction technologies.
This chapter is dedicated to the application of antibodies in multi-analyte immunoassays for water monitoring with a focus on their application in fluorescence based optical biosensors. This includes practical aspects during assay development like affinity, cross-reactivity, and the validation process. In addition, a strategy to use antibodies with high cross reactivities (e.g. to the chemical group of estrogens) for the detection of sum concentrations will be explained as well as a strategy to reduce matrix effects caused by dissolved organic carbon.