An approach to the construction of an immunoarray for differentiating and quantitating cross reacting analytes

We demonstrate the construction of an immunoarray to categorize, identify and quantitate different triazine herbicides or their environmental metabolites in water. In a first step cluster analysis is used to examine the performance of a small subset of antibodies out of a larger library, and hence to select a small array that is capable of categorizing the triazine herbicides into different groups. At the 1 ppb level it is possible to categorize an analyte as a chloro-s-triazine, a hydroxy metabolite, or as a methoxy/methylthio substituted triazine when using only 2-4 antibodies. At higher concentrations even the identity of the triazine can be determined with the same number of antibodies. A selected combination of antibodies is then used to identify and quantify unknowns by comparing their immunoassay responses to an array of calibration curves and using the maximum likelihood criterion.