Dipstick immunoassay format for atrazine and terbuthylazine analysis in water samples

A new dipstick immunoassay format for terbuthylazine determination, based on the use of polystyrol strips as antibody coating support, is described. The terbuthylazine calibration curve shows a linear measuring range between 1.2 and 10 mu g/L. Real water samples were analyzed, and results correlate well with those from gas chromatography (GC/MS) and ELISA. No false negative results were evidenced. The dipstick immunoassay format for atrazine determination (Wittmann et al. Analyst 1996, 121, 863-869) was also used for the analyses of the same samples. Some false positive results were obtained, probably due to cross-reactivity of the atrazine monoclonal antibody for terbuthylazine. At this developmental stage, these dipsticks can be very useful as a qualitative/semiquantitative "field test" for identifying "positive'' samples, reducing the number of samples to be reanalyzed in the laboratory, according to analytical standard methods (GC). Further improvements are possible to optimize the whole system on the strictly analytical aspects.