AUTOMATED QUASI-CONTINUOUS IMMUNOANALYSIS OF PESTICIDES WITH A FLOW-INJECTION SYSTEM

Chemical methods (HPLC, GC/MS) for the control of pesticides in water at low concentrations are time-consuming, expensive and need sample pre-concentration. Immunoassays offer the potential of rapid, inexpensive, sensitive and specific detection methods. This paper presents a flow injection system that is based on immunochemical reaction and which provides the opportunity for automated, quasi-continuous measurements for screening water samples for the presence of pesticides. The method of flow injection immunoanalysis (FIIA) was compared with competitive ELISA (enzyme-linked immunosorbent assay). It is possible to measure in the range of interest of 0.1-mu-g litre-1, which is the limiting value of the European drinking water directive. Measurements were made for the triazine herbicides atrazine and propazine, which both cross-react with the polyclonal antiserum used. Furthermore, this device includes a new development of a membrane reactor for the exchange of used biological material, in this case antibodies. A brief comparison of ELISA and FIIA is presented, giving an overview of some aspects of the assays.