Abstract: An FIA method for the determination of triazine herbicides was developed based on affinity chromatography with post-column fluorescence detection. Triazine herbicide derivatives were immobilized on to oxirane acrylic beads and the beads were packed into glass tubes (3-8 cm x 1.5 mm i.d.) to form the affinity column. The FIA cycle involved the following steps: (i) loading of the affinity column with fluorescently labelled anti-herbicide antibodies, flow stopped for 15 min; (ii) injection of 100-200 µL of atrazine solution, flow stopped for 20-40 min; (iii) post-column fluorescence detection of the released fluorescent antibodies with a laser-based fluorimeter equipped with a pulsed N2 laser (337.1 nm) and a 610 nm interference filter. The antibodies were labelled with the fluorescent Eu(III) chelate, W8044-Eu, and the flow rate was 0.25 ml/min throughout (mobile phase not given). The complete FIA cycle required 45-75 min. The linear dynamic range of the calibration graph covered three orders of magnitude and the detection limit was 1 µg/l.

Abstract: An FIA method was developed for screening natural water for chloro- and methyl-thiotriazines. The FIA manifold was equipped with a membrane separation module fitted with a microporous polypropylene membrane (0.025 mm thickness, 0.04 µm pore size) which allowed the analytes to be extracted from a continuously circulating sample stream and to be pre-concentrated into a stationary acceptor solvent (100 µL hexane). At the end of the 3 min pre-concentration period, the acceptor solution was propelled to the detection cell (18 µL volume) of the diode-array spectrophotometer where the spectrum for 220-250 nm was recorded. The overlapping signals of chloro- and methyl-thiotriazines were resolved by a partial least squares method. The RSD (n = 10) for the analysis of binary mixtures containing 80-400 µg/l of terbutryne and propazine were 6%. The detection limits for terbutryne and propazine were 4.8 and 4.5 µg/l, respectively.

Abstract: Automated immunochemical analysis offers an inexpensive online monitoring or off-line screening of different drinking water sources without extensive sample preparation and without using organic solvents. Two prototype system instruments, one online the other off-line, were studied within the European project, Program Life. Results discussed were performed with the off-line device, where standards and samples are supplied in sep. vials. Automated anal. depends on an extended time of operation without attendants; therefore, all reagents, especially immunoreagents (antibody and enzyme-tracer), should have a stability of at least 14 days. Different stabilization methods were studied. Best stability (at least 14 days) was achieved by adding 0.5% BSA (bovine serum albumin) and 0.5% micro-O-protect, together with storage at 4°C. To reduce buffer salts, which would be discharged to the environment during continuous FIIAA (flow injection immunoaffinity anal.), a comparison of 40 and 4 mM PBS (phosphate buffered saline) as carrier buffer was made. Results showed there was no difference in performance between the 2 carrier buffers. As an example, the system was applied to determine diuron in actual water samples which contained high concentrations of humic substances (9.5 mg/L DOC [dissolved organic carbon]). Samples were collected from groundwater and different water treatment stages of the water supply station in Fuhrberg, Germany, and afterwards spiked with diuron. As a reference method, samples were analyzed by conventional micro-titer plate ELISA, using the same immunoreagents. Determined amounts were generally in good agreement with spiked amts.; FIIAA produced better results.

Abstract: Water sample (100 ml) was mixed with 7.8 g 1 M ammonium acetate and 1 mL 100 ng/ml 2H5-ethylamine-atrazine (internal standard), adjusted to pH 7 with NH4OH or glacial acetic acid, then a portion (30 ml) was applied to a 1 g Baker PolarPlus SPE cartridge at 3 ml/min. After washing with water, triazines and their degradation products were eluted with 2 x 2.5 mL methanol, the combined eluate was evaporated to 1 ml, diluted to 10 mL with 0.11 M ammonium acetate, and portions (2 or 5 ml) were analyzed directly by flow injection thermospray tandem MS (operating conditions given). Compounds were identified with µtiple reaction monitoring, where four product ions were analyzed after a prior screening procedure. Calibration graphs were linear from 0.05-1 µg/l. Detection limits were 0.05-0.15 µg/l and 0.2-0.45 µg/l for triazines and their degradation products, respectively. The corresponding recoveries were generally >82% and >60%. The RSD (n = 10) were ?. Results were comparable to those obtained by GC.