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Dispersive liquid-liquid microextraction based on solidification of floating organic drop and fluorescence detection for the determination of nitrated polycyclic aromatic hydrocarbons in aqueous samples, Microchemical Journal (2016), Abstract In this study, a dispersive liquid-liquid microextraction method based on the solidification of a floating organic drop (DLLME-SFO) combined with molecular fluorescence detection was developed for the analysis of nitrated polycyclic aromatic hydrocarbons in environmental samples. Parameters affecting the efficiency of the extraction procedure were evaluated and optimized, including the nature of the dispersant agent, extractant and dispersant volumes, salt addition effect, and extraction time. Additionally, various strategies in the emulsion formation process were assayed.After optimization, the values obtained for limits of detection and quantification for 3nitrofluoranthene were 2.3 ng mL -1 and 5 ng mL -1 respectively, and for 9nitroanthracene 1.7 ng mL -1 and 2.5 ng mL -1 . The recoveries values ranged from 95% to 100% and the enrichment factor attained varied from 380 to 400-fold. The developed method was successfully applied to the analysis of lake water and drinking water samples. The results indicated that the proposed approach is a novel, sensitive, fast and reproducible methodology suitable for the analysis of traces of environmentally important nitrated polycyclic aromatic hydrocarbons in water samples.

The present work aimed to characterize and to improve the production of the siderophore produced by Kosakonia radicincitans and apply it to control of phytopathogenic fungi. The siderophore, characterized by liquid chromatography coupled to tandem mass detection (LC-MS/MS), was identified as enterochelin. The improvement of its production was carried out using different conditions. The higher production of enterochelin (45 mg g -1 dry weight biomass) was reached in a medium with lactose as the carbon source, 0.82 mol.L -1 of iron, at 28°C and 200 rpm.The siderophore at 60 mg L -1 of concentration inhibited the conidia germination and the mycelial growth of Penicillium expansum, Botrytis cinerea, Rhizopus sp., Alternaria sp. and Cladosporium cladosporoides. Biocontrol of Botrytis cinerea and Penicillium expansum were performed in apple fruit using Kosakonia radicincitans and enterochelin, alone or in a mixture. The mixture was the more effective. In this case, the reduction of decay provoked for B.cinerea reached 52%.