Development of a new automatic on-site detector of pesticides in natural waters by photo induced fluorescence, application to three phenylurea and benzoylurea herbicide.

Prototypes of on-site automatic photo induced fluorescence detectors of pesticide in natural waters are set up and applied for the determination of the benzoyl- and phenylurea pesticides, namely fluometuron, monolinuron and diflubenzuron. As these pesticides present no native fluorescence the set up system use the photo conversion under UV irradiation of these pesticides into highly fluorescent photoproducts. A first system, called AUTOPIF, (evolution the commercial AQUAPOD system) is develop using a detection via a diode array spectrometer. To improve the sensitivity of the method, a second system, called AUTOPIF+, is developed with a more resolute spectrometer and an intensified CCD camera detection. Analytical applications were carried out in aqueous solution and detected on line with the AUTOPIF and AUTOPIF+ system. The calibration curves are linear over one order of magnitude, and the limits of detection are in the µg mL-1 range. The analytical performances of these methods for the determination of the three pesticides are satisfactory in comparison to other classical PIF methods published for the determination of phenylurea pesticides in aqueous solutions. Our results show that the AUTOPIF and AUTOPIF+ methods are versatile, sensible and can be easily applied as an alert system to detect pollutant residues in naturals waters over a threshold value.

A new direct laser photo-induced fluorescence method coupled on-line with liquid chromatographic separation for the simultaneous determination of anilides pesticides.

A new direct laser photo-induced fluorescence high performance liquid chromatography (DL-PIF-HPLC) method is developed for the simultaneous determination of three anilide pesticides, namely carboxin, monalide and propanil. DL-PIF-HPLC uses a tunable Nd:YAG-OPO laser to obtain fluorescent photoproduct(s) and to simultaneously analyze their fluorescence in a short acquisition time with an intensified CCD camera, which improves the selectivity (by choosing the suitable excitation wavelength), increases the sensitivity (due to the high energy of the laser beam) and reduces the time of analysis, relative to the classical PIF methods. However, one of the main drawbacks of PIF methods is the presence of interferences with other compounds, such as other pesticides from the same group yielding similar fluorescent photoproducts, which reduces their selectivity. The analytical interest of DL-PIF-HPLC to avoid these interferences is demonstrated. The DL-PIF spectra, chromatographic conditions and analytical performances of DL-PIF-HPLC are presented for the simultaneous determination of three anilide pesticides. The calibration curves are linear over one order of magnitude and the limits of detection are in the ng mL(-1) range. The new DL-PIF-HPLC system has the advantage to combine the performances of both techniques, DL-PIF and liquid chromatography, and to improve the analysis selectivity.

Photochemically-induced fluorescence properties of two benzoyl- and phenylurea pesticides and determination in natural waters.

A photo-induced fluorescence (PIF) method was developed for the determination of two benzoyl- and phenylurea pesticides, namely diflubenzuron (DFB) and fenuron (FEN). The photoconversion under UV irradiation of both pesticides into strongly fluorescent photoproducts was performed in several media (methanol, ethanol, acetonitrile, pH4 aqueous solution and pH4 water-methanol (30:70, v/v) mixture). PIF parameters were optimized. Analytical figures of merit for the PIF determination of DFB and FEN were satisfactory, with rather wide linear dynamic range (LDR) values of one to two orders of magnitude, relatively low limit of detection (LOD) values of, respectively, 9-24 ng/mL for DFB and 1-28 ng/mL for FEN, and limit of quantification (LOQ) values of, respectively, 30-80 ng/mL for DFB and 4-95 ng/mL for FEN, according to the medium. Relative standard deviation (RSD) values were in the range 1.7-5.6%. PIF was validated by comparing its analytical performances to those of a standard UV absorption spectrophotometric method. The optimized PIF method was applied to the quantitative analysis of both pesticides in various spiked natural water samples collected in a Senegal agricultural area by the standard addition procedure prior to extraction steps in dichloromethane, with satisfactory mean recovery percentage values (97.0-105.3 for DFB and 98.3-102.8% for FEN). An interference study of foreign species, including pesticides and inorganic ions, likely to be present in natural waters, was also carried out.

Determination of phenylurea pesticides by direct laser photo-induced fluorescence.

A direct Laser Photo-Induced Fluorescence (DL-PIF) method is developed for the determination of two phenylurea pesticides, namely fenuron and diflubenzuron. The DL-PIF method uses a tunable Nd:YAG-OPO Laser to obtain the photoproduct(s) and to simultaneously analyse their fluorescence in a short acquisition time on an intensified CCD camera. Compared to classical PIF methods, the use of a tunable laser improves the selectivity (by choosing the suitable excitation wavelength), increases the sensitivity (due to the high energy of the beam) and also reduces the time of analysis. The analytical performances of this method for the determination of both pesticides are satisfactory in comparison to other classical PIF methods published for the determination of phenylurea pesticides. The calibration curves were linear over one order of magnitude and the limits of detection were in the ng mL(-1) range. Satisfactory recoveries were obtained in the analysis of both pesticides in river and sea water spiked samples.

[Variability of skin test on both tuberculosis and co infected patients with HIV under tuberculosis treatment]. / Variabilite de l'intradermoreaction a la tuberculine chez les tuberculeux et coinfectes (VIH+) sous traitement antituberculeux.

To evaluate the variability of tuberculin skin test (TST), we did a prospective study in the pneumology unit of the teaching hospital at Point G and in the tuberculosis unit of the health district II at Bamako, Mali TST was applied two times to every patient more than 18 years old: at the beginning before the tuberculosis treatment (tst1) and after 2 months (tst2). For all 113 patients followed in both units, 41 were enrolled in this study (36, 2%). The mean age of patients was 37.9 years and 73.2% were male.(sex proportion was 2.72 for male). The different forms of Tuberculosis were: 63.4% of tuberculosis with smear positive(TSP); 7.3% of tuberculosis with smear negative(TSN); and 29,3% of disseminated tuberculosis. 22% of the patients were HIV positive. The tst1 was positive for 58.5% of the patients(11.11% of the HIV positive patients and 78.13% of the HIV negative). The diameter of indurations of the TST increased considerably during the treatment mainly with patients infected by HIV. The TST test can be an indicator of follow op for these patients who had less AFB most of time?

[Profile of deceased patients who died as a result of microscopy-positive pulmonary tuberculosis: impact of HIV status]. / Profil des patients decedes de tuberculose pulmonaire a microscopie positif (TPM+): influence du statut VIH.

In order to study the profile of patients who died of pulmonary tuberculosis with positive smear under tuberculosis chemotherapy and the impact of HIV status, a prospective study over eight months from 1 November 2005 to 30 June 2006 was conducted in tuberculosis department CHU point G. Among patients hospitalized for tuberculosis all forms, 73 cases of pulmonary tuberculosis were recorded including 54 sputum smear-positive (73.9%). The analysis focused on 28 deaths among pulmonary tuberculosis smear positive (prevalence of 51,85%). The age group of 16-35 years was the most represented with a sex ratio of 2.5. The different causes of morbidity which had a negative influence on the lethality of TB patients in order of importance were: the extent of the lesions (71.4%), HIV/AIDS status (63.15%), smoking (50 %) and a history of tuberculosis (25%) (p = 0.02). The deaths occurred early during the first week of hospitalization. The search for morbidity factors in any patient with tuberculosis should be systematical to improve their care.

Profil des patients decedes D (TMP+) : influence du statut VIH

Dans le but d'etudier le profil de patients decedes de tuberculose pulmonaire a microscopie positive (TPM+) sous chimiotherapie antituberculeuse et l'influence du statut VIH; une etude prospective sur huit mois; du 1er novembre 2005 au 30 juin 2006 a ete menee dans le service de pneumo phtisiologie du CHU de point G. Parmi les malades hospitalises pour tuberculose toutes formes confondues; 73 cas de tuberculoses pulmonaires ont ete repertories dont 54 cas de tuberculose a frottis positif soit 73;9. L'analyse a porte sur 28 deces parmi les cas de tuberculose pulmonaire a frottis positif soit une prevalence de 51; 85. La tranche d'age de 16-35 ans etait la plus representee avec un sex-ratio de 2;5. Les differents facteurs de morbidite qui ont influence negativement sur la letalite des patients tuberculeux par ordre d importance etaient : l etendue des lesions (71;4); ; le statut VIH/SIDA ( 63;15) ; le tabagisme (50) et des antecedents de tuberculose (25) (p= 0;02). Les deces survenaient precocement au cours de la premiere semaine d'hospitalisation. La recherche des facteurs de morbidites chez tout patient tuberculeux devrait etre systematique pour ameliorer leur prise en charge globale

[HIV/AIDS impact in pulmonary tuberculosis with negative microscopy in pneumology service at Point "G" hospital]. / Impact du VIH/SIDA dans la tuberculose pulmonaire à microscopie négative (TPM-) dans le service de pneumophtisiologie à Bamako.

This study was opened and conducted from colligated patient folders during 5 years (from January 1999 to December 2003). The main objective was the description of epidemiological, diagnostically and prise and prise of charge aspects of microscopy negative pulmonary tuberculosis. Patients were enrolled in this study in accordance to WHO criteria. During these 5 years, pulmonary tuberculosis has constituted 72.2% on all froms of tuberculosis with 20.2% of microscopy negative pulmonary tuberculosis. The BCG vaccine scar has been observed in 50.8% of cases. The IDR was negative in 21.3% of cases; this rate was about 68.1% in HIV positive patients. More than 60% of the patients have more than 3 negative bacilloscopy. The 69.4% of our patients have been hospitalized and 64% have been treated with III category system.

Impact du VIH/SIDA dans la tuberculose pulmonaire à microscopie négative (TPM -) dans le service de pneumophtisiologie à Bamako

Il s'agit d'une étude ouverte sur des dossiers colligés durant une période de cinq ans ( Janvier 1999 à Décembre 2003), qui avait pour objectif principal de décrire les aspects épidémiologiques, diagnostiques et la prise en charge de la TPM - .Les patients sont inclus dans l'étude pour TPM- selon les critères de l'OMS. Pendant cette période de cinq ans, la tuberculose pulmonaire (TP) a constitué 72,1% des cas de tuberculoses toutes formes sur lesquelles 20,2% de TPM- . La cicatrice BCG était présente dans 50,8% des cas. L'IDR était négative dans 21,3% des cas, ce taux atteint 68,1% chez les patients VIH positifs. Plus de 60% de nos patients ont réalisé plus de 3 bacilloscopies qui sont restées négative. La sérologie VIH était positive chez 51,1% des patients testés. L'hospitalisation a concerné 69,4% de nos patients, 64% ont été traité par le régime de la catégorie III