REFLECTOMETRIC INTERFERENCE SPECTROSCOPY FOR THE DETERMINATION OF ATRAZINE IN NATURAL-WATER SAMPLES

We assessed the performance of a new sensing device based on reflectom etric interference spectroscopy (RIFS) for the determination of atrazi ne in water samples. The correlation coefficients between concentratio ns of natural water samples measured by RIFS and by HPLC/GC were highl y significant (0.903; p < 0.001) for the 31 surface water and groundwa ter samples tested, but very poor (0.190; p < 0.5) for the 9 lysimetri c plate water samples. Marked interferences were observed with humic a cid solutions, probably due to strong nonselective polyanion-polycatio n binding to the transducer surface, which involves a basic aminodextr an. The detection limit was 0.35 mu g/L. Since there was a significant cross-reactivity of simazine and terbutylazine, the present system mi ght be used for screening groups of pesticides rather than for the det ermination of a single molecule. The total duration of one determinati on, 15 min, enables semicontinuous measurements without any sample pre treatment. No significant alteration of the sensor was observed after 160 determinations. These results demonstrate the potential of RIFS as a new technology for monitoring pesticides in natural water samples.