Analysis of Oxadiazon Herbicide in Natural Water Samples by a Micellar-enhanced Photo-induced Fluorescence

International audienceA micellar-enhanced photo-induced fluorescence (ME-PIF) method was developed to analyze, for the first time, oxadiazole herbicide (namely oxadiazon) in natural water samples. Photo-conversion under UV irradiation of the herbicide into strongly fluorescent photoproducts was performed in aqueous solution and in the presence of two surfactants, cetyltrimethylammonium chloride (CTAC) or Tween 20, at micellar concentrations. The ME-PIF parameters were optimized. The ME-PIF method gave very good results with satisfactory analytical performance for the determination of a selected pesticide with concentration linear dynamic ranges of over one to two orders of magnitude. It yielded good reproducibility (RSD values of between 3.6 and 9.6%) in tap, river and sea water spiked samples, and the limits of detection were in the ng mL-1 range

Determination of Agmatine Rate by Spectrofluorimetric Method in Alkaline Medium: Optimization and Application on Shrimp.

International audienc

Spectrofluorimetric determination of beta-blockers atenolol and bisoprolol fumarate residues in Senegal natural waters

A spectrofluorimetric method was developed to determine residues of two β-blockers, atenolol (AT) and bisoprolol fumarate (BF), in Senegal's natural waters. The electronic absorption and fluorescence spectral properties of both β-blockers were investigated in several organic solvent mixtures [e.g., MeOH/H2O (60/40 v/v), cyclodextrins (β-cyclodextrin, HP-β-CD], and in the presence of surfactants (SDS, Triton X, Tween 80). After optimization, satisfactory analytical figures of merit were obtained for the determination of both β-blockers: concentration linear dynamic range of over one to two orders of magnitude, limits of detection (LODs) from 1.3 to 5.4 ng/ml for BF and from 1.2 to 3.7 ng/ml for AT, limits of quantification (LOQs) from 4.5 to 18.1 ng/ml for BF and from 4.0 to 12.5 ng/ml for AT. Relative standard deviations (RSDs) were between 2.1 and 5.3 %, according to the β-blockers. The spectrofluorimetric method was applied to the analysis of fortified river water and wastewater (effluent) collected in Senegal and France and spiked with both β-blockers. It yielded good recovery values, from 93.3 to 107.8 % for AT and from 97.4 to 108.9 % for BF. Our results demonstrated the simplicity, rapidity, and sensitivity of the spectrofluorimetric method to quantify residues of β-blockers in environmental waters

Septic hip dislocations in children in a developing country

Purpose: To report on a radiological issue and therapeutic aspects encountered in septic hip dislocations in a developing country. Patients and Methods: Nineteen children among whom 11 boys and 8 girls aged on average 5.3-years old presented 7 recent and 12 late hip dislocations. Those dislocations were distributed into in category 1: dislocations without associated lesion; category 2: dislocations associated with minor lesions; category 3: dislocations associated with major lesion. Ten children who presented an elevated erythrocyte sedimentation rate (ESR) received antibiotics. An arthrotomy was performed in children with a recent dislocation. Traction was performed in all children with an average duration of 5 weeks. The results were considered good, intermediate or bad using two parameters: ESR and reduction of dislocation. Results: 2 category 1 dislocations, 6 category 2 dislocations and 11 category 3 dislocations were noted. As concerns the recent dislocations, there were 2 category 1 dislocations and 5 category 2 dislocations. For late dislocations, 1 category 2 and 11 category 3 dislocations were recorded. There were 8 good results and 11 bad results. The good results concerned 7 recent dislocations and one late dislocation. The bad results concerned exclusively late dislocations. Conclusion: In children with septic hip dislocations, the good results concern almost exclusively recent dislocations but arthrotomy and immobilization must be done early

Ultraviolet Photo-Induced Fluorescence Followed by Laser Excitation (UV-PIF-LE) for the Determination of Pesticides in Natural Waters

International audienceA new method was developed for determining trace amounts of pesticides, using an ultraviolet (UV) lamp to obtain photo-induced fluorescent (PIF) compounds, and then using laser excitation (LE) by a tunable source to excite and simultaneously characterize their fluorescence over a short acquisition time using an intensified charge-coupled device camera. This new UV-PIF-LE method was applied to determine isoproturon, oxadiazon, and fipronil in natural waters. This approach represents an improvement on the previously published direct laser photo-induced fluorescent (DL-PIF) approach that utilized the inclusion of a supplementary UV irradiation device in the experimental setup, permitting the separation of the formation and detection steps for the PIF analytes. This evolution improves the selectivity and increases the sensitivity while maintaining a short analysis time. The UV-PIF-LE method gave very good results with satisfactory analytical performance for the determination of the selected pesticides. This approach also demonstrated good reproducibility, with relative square deviation values between 3.3% and 6.3%, for spiked river water and seawater samples with detection limits in the ng mL−1 range

Development of a photo-induced fluorescence method for determination of anilide pesticides used in Senegal

International audienc

Development of a photo-induced fluorescence method for determination of anilide pesticides used in Senegal

International audienc

Development of a photo-induced fluorescence method for determination of anilide pesticides used in Senegal

International audienc

Rapid removal of fungicide thiram in aqueous medium by electro-Fenton process with Pt and BDD anodes

International audienceThe electro-Fenton (EF) process was used to assess the electrochemical degradation of the fungicide thiram and its complete removal from water using an undivided electrolytic cell equipped with Pt or BDD anode and carbon felt cathode. Hydroxyl radicals, produced homogeneously in bulk solution from electrochemically generated Fenton's reagent (• OH) and heterogeneously on the anode surface (M(• OH)) from oxidation of water, reacted with thiram leading to its fast oxidation. Oxidative degradation and mineralization kinetics were monitored by chromatographic analysis (HPLC) and total organic carbon (TOC) measurements. The electrochemical degradation of thiram by hydroxyl radicals followed a pseudo-first-order reaction kinetics with an absolute rate constant kabs(Thir) of 5.54 (± 0.03) × 10 9 M-1 s-1 , determined by competition kinetics method. The TOC removal rate values were found significantly higher with BDD anode than Pt anode. Thus, almost complete mineralization (92%) of thiram solution was obtained when using BDD anode. 2 These results highlight the major role of heterogeneous BDD(• OH) formed in the mineralization of thiram. The contribution of homogeneous • OH in mineralization of thiram was found relatively low due to its specific aliphatic structure. The efficiency of the EF process was evaluated by determining mineralization current efficiency and energy consumption per gram of TOC removed. Degradation by-products and inorganic ions, such as nitrate (NO3 −), nitrite (NO2 −), ammonium (NH4 +) and sulfate (SO4 2−) formed during mineralization process, were identified by GC-MS and ionic chromatography analyses and a plausible mineralization pathway was proposed