Standardization of Immunoassays for Water and Soil Analysis

Immunoassays have become a valuable tool in the field of environmental analysis, especially for screening a large number of samples within a short time. One of the approaches to guarantee the reliability and the comparability of the results is to prescribe a standardized method in detail. In Germany, the Immunoassay Study Group as a working group of the German Standards Institute DIN and the German Chemical Society is dealing with the standardization of immunoassays for pesticides and environmental pollutants. In 1994, a draft standard has been completed on selective immunoassays for the quantitative determination of plant treatment and pesticide agents in drinking, ground and surface water. In order to prove the feasibility of the standard procedure, round robin tests were simultaneously carried out for the herbicide atrazine and the environmental pollutant TNT including spiked and unspiked ground and surface water samples. The data show that the requirements of the guideline, the quantitative determination of a single pesticide, can be met, even in the presence of related compounds of environmental significance. An interlaboratory trial, carried out in 1995 with sixteen participants, provides the basis for the final DIN guideline for selective immunoassays.