Abstract: A sequential injection instrument (ALITEA, USA) with a photometric and fluorometric detection unit S2000 (Ocean Optics) was employed for the development of flow injection immunoanalysis (FIIA). The monoclonal antibodies against atrazine, simazine and 2,4-D were immobilized on aminopropyl glass particles by means of avidin/biotin system and packed in plexiglass column of 18 µl volume. Assay characteristics for individual antibody-reactors and regeneration effectivities for acid and alkaline solutions are described. An attempt to prepare a functional mixed antibody-reactor has not achieved success since regeneration conditions found for individual reactors were not compatible with one performance protocol.

Abstract: A waveguide surface plasmon resonance biosensor, equipped with low-index glass waveguides and a 10 mW He-Ne laser (632.8 nm), was evaluated for determining simazine in natural waters. The interaction length (3 mm) of the biosensor was coated with a Au film (53±3 mm thickness) and a triazine derivative, 4-chloro-6-(isopropylamino)-1,3,5-triazine-2-(6'-amino)caproic acid. The biosensor was incorporated into a FIA system and PBS of pH 7.4 was used as the carrier stream. The assays were carried out by incubating the buffered sample with simazine antibodies for 5 min. A portion (100 µL) of the solution was injected into the FIA system and the carrier stream flow was stopped for 8 min when the sample plug reacted the detector cell to allow the free antibodies to react with the immobilized triazine derivative. After recording the signal the biosensor was regenerated by pumping 2 g/l pepsin in PBS of pH 1.9 and 1% propionic acid in aqueous 50% acetonitrile. The system was calibrated for up to 100 µg/l simazine, the detection limit was 0.2 µg/l and the day-to-day RSD (n = 5) were The cross reactivities of atrazine and terbutylazine were 61% and 62%, respectively. The method was applied to surface and ground water samples and the results were confirmed by chromatographic analysis. The method was not suitable for analyzing soil water samples due to the strong non-selective polyanion-polycation binding to the transducer surface.

Abstract: A microporous glass fiber disk (0.9 cm diameter) was mounted between two plastic layers having a central hole of 0.32 mm diameter. The whole was clamped between two Plexiglass chambers. One of the chambers contained a flow-through electrochemical cell, through which the carrier solution was pumped. A Ag/AgCl reference electrode was immersed in the waste of the carrier solution. The second chamber was equipped with a second Ag/AgCl reference electrode and a potential of 25 mV was applied between the two electrodes. Formation of stabilized BLM was effected by the method of Nikolelis et al. (Ibid.,1995, 7, 531 and Anal. Chem., 1995, 67 936), using solutions of lyophilized egg phosphatidylcholine and dipalmitoylphosphatidic aci d in hexane/ethanol (4:1). The carrier electrolyte solution consisted of 0.1 M KCl/10 mM HEPES buffer of pH 8 containing 1 mM calcium ions. The herbicide solutions were injected into the carrier stream and the resulting transient current signal was recorded. Calibration graphs were linear up to 1.4 ppm, 210 ppb and 300 ppb, respectively, for atrazine, simazine and propazine and the corresponding detection limits were 40, 8 and 20 ppb.