A simple and sensitive flow-injection (FI) method is reported for the determination of thiram and aminocarb pesticides in natural water samples based on the strong enhancing effects of these pesticides on the tris(2,2′-bipyridyl)ruthenium(II)-diperiodatoargentate(III) (Ru(bipy)3 2+ -DPA) chemiluminescence (CL) system. Under the optimum experimental conditions, the CL intensity was linear over the range of 1.0 -1000 and 1.0 -10000 ng mL -1 (R 2 = 0.9998 (n = 7) and 0.9994 (n = 11)) for thiram and aminocarb, respectively, with relative standard deviations (RSDs; n = 3) in the range 1.0 -2.6%. The limits of detection (S/N = 3) were 0.1 ng mL -1 for both pesticides with injection throughputs of 150 h -1 . The key chemical and physical variables (reagent concentrations, flow rates, sample volume, PMT voltage) were optimized and potential interferences investigated. The method was successfully applied to natural water samples and the results obtained were not significantly different (95% confidence interval) from results obtained by the previously reported FI-CL and HPLC methods. Thiram could be determined in the presence of aminocarb using Triton X-100. The possible CL reaction mechanism is also discussed briefly.

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A limited number of FI-CL methods have been reported based on the use of the Cu(III) complex in aqueous phosphoric acid and sulfuric acid solutions for the determination of ofloxacin, levofloxacin and enrofloxacin in pharmaceutical preparations, urine and veterinary preparations with detection limits (S/N = 3) 2016 © The Japan Society for Analytical Chemistry † To whom correspondence should be addressed. E-mail: yaqoob2001@hotmail.com Chemiluminescence (CL) with a flow-injection method is reported for the determination of thiabendazole (TBZ) fungicide based on its enhancement effect on diperiodatocuprate(III) (DPC)-sulfuric acid-CL system. The calibration graph was linear in the concentration range of 1 -2000 μg L -1 (R 2 = 0.9999, n = 8) with a limit of detection (S/N = 3) of 0.3 μg L -1 . The injection throughput was 160 h -1 with relative standard deviations (RSD, n = 4) of 1.1 -2.9% in the concentration range studied. The experimental variables e.g., reagents concentrations, flow rates, sample volume, and PMT voltage were optimized, and the potential interferences were investigated individually. The method was successfully applied to the determination of TBZ in water samples showing good agreement and recovery in the range of 92 ± 2.2 -108 ± 3% (n = 3) using dispersive liquid-liquid micro-extraction (DLLME). The possible CL reaction mechanism for DPC-sulfuric acid-TBZ is also discussed.Keywords Flow injection analysis, DPC, chemiluminescence, thiabendazole, water samples

A flow-injection (FI) method is reported for the determination of Mn(II), maneb and mancozeb fungicides based on the catalytic effect of Mn(II) on the oxidation of lucigenin and dissolved oxygen in a basic solution. The Tween-20 surfactant has been reported for first time to enhance lucigenin chemiluminescence (CL) intensity in the presence of Mn(II) (53%) and maneb and mancozeb (89%). The calibration graphs were linear in the concentration range of 0.001-1.5 mg L(-1) (R(2) = 0.9982 (n = 11) with a limit of detection (S/N = 3) of 0.1 µg L(-1) for Mn(II) and 0.01-3.0 mg L(-1) [R(2) = 0.9989 and R(2) = 0.9992 (n = 6)] with a limit of detection (S/N =3) of 1.0 µg L(-1) for maneb and mancozeb respectively. Injection throughputs of 90 and 120 h(-1) for Mn(II) and maneb and mancozeb respectively, and relative standard deviations of 1.0-3.4% were obtained in the concentration range studied. The experimental variables, e.g., reagents concentrations, flow rates, sample volume, and photomultiplier tube voltage, were optimized and potential interferences were investigated. The analysis of Mn(II) in river water reference materials (SLRS-4 and SLRS-5) showed good agreement with the certified values incorporating an on-line 8-hydroxyquinoline chelating column in the manifold for removing interfering metal ions. Recoveries for maneb and mancozeb were in the range of 92 ± 5 to 104 ± 3% and 91 ± 2 to 100 ± 4% (n = 3) respectively. The effect of 30 other pesticides (fungicides, herbicides and insecticides) was also examined in the lucigenin-Tween-20 CL system.

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