A procedure for the immunoanalysis of samples containing one or more members of a group of cross-reacting analytes

The information obtained from a single-antibody immunoassay can be ambiguous when the identity of the analyte is unknown and could be one of a group of compounds all having different affinities for the antibody. If we allow the possibility of mixtures of analytes the difficulty of the situation is aggravated. However, additional information can sometimes be obtained by assaying with a number of different antibodies. We demonstrate a rationale for identifying and quantifying analytes from a group of candidates, and illustrate the application of our method with an example from the class of s-triazine herbicides. Using a four-antibody array, correct identification and accurate quantification were usually achieved for singleanalytes samples in the low ppb range. Mixtures of analytes were recognized as such but were more difficult to classify correctly, with some confusion arising between members of subgroups, particularly within the methoxy/methylthio substituted triazines. The mathematical perspective is used to suggest directions for improving the experimental performance of multianalyte immunoassay.