Rapid method for on-site determination of atrazine residues in water samples.: Assay optimisation

A rapid and sensitive dipstick immunoassay for atrazine has been developed. The optimisation of different parameters, such as substrate dilution, assay time and simultaneous versus sequential protocol, by means of an immunofiltration device is described. The assay is based on the competitive principle and uses a polyclonal antibody immobilized on an Immobilon-P membrane and alkaline phosphatase as enzyme tracer. The test takes about 10min and has a visual detection limit for atrazine of 10mugL(-1). Cross-reactivity of polyclonal sera to atrazine and propazine are similar, decreasing 10-fold for simazine and terbuthylazine and 100-fold for prometryn and ametryn. Based on the good reproducibility obtained (90% of positive response) the developed dipsticks can be very useful as a qualitative or semiquantitative on-site test for atrazine determination in water samples.