andre fouquet - Academia.edu (original) (raw)

Papers by andre fouquet

Journal of AOAC INTERNATIONAL, 2007

A multiresidue method was developed to measure low levels of 8 fluoroquinolones (norfloxacin, ofl... more A multiresidue method was developed to measure low levels of 8 fluoroquinolones (norfloxacin, ofloxacin, danofloxacin, ciprofloxacin, desethylene ciprofloxacin, enrofloxacin, sarafloxacin, and difloxacin) and 4 quinolones (oxolinic acid, flumequine, nalidixic acid, and piromidic acid). Method detection limits range from 0.1 ng/g for quinolones to 0.4 ng/g for fluoroquinolones. Average recoveries range from 57 to 96%, depending on analyte and commodity; relative standard deviations are all less than 18%. The drugs are extracted from tissues using a mixture of ethanol and 1% acetic acid, diluted in aqueous HCl, and defatted by extraction with hexane. The compounds are further isolated using cation-exchange solid-phase extraction and measured using liquid chromatography with electrospray tandem mass spectrometry detection. The method has been evaluated and applied to the analysis of salmon, trout, and shrimp. Detectable residues were observed in 10 out of 73 samples, at concentrations ...

Analusis, 1997

Quantification d'ultratraces de pesticides organophosphores et organoazotes dans des eaux de ... more Quantification d'ultratraces de pesticides organophosphores et organoazotes dans des eaux de surface. Une methode a ete mise au point pour analyser 16 pesticides organophosphores et organoazotes dans les eaux de surface. Les echantillons de 35,7 L ont ete filtres sur filtre de fibre de verre (0,7 μm) pour separer les matieres en suspension et la phase dissoute (eau filtree). Les matieres en suspension ont ete extraites au Soxhlet et l'eau filtree avec l'extracteur a grands volumes de Goulden (GLSE) avec du dichloromethane. Les pesticides ont ete analyses par chromatographie en phase gazeuse a l'aide des colonnes capillaires DB-5 et DB-210 et d'un detecteur azote-phosphore (GC-NPD). A l'exception de la metribuzine, tous les pesticides presentaient des recuperations plus elevees dans l'eau distillee (71-95 %) que celles retrouvees dans l'eau de surface filtree (3-106 %). Les recuperations sur les blancs de filtre se situent entre 39 et 118 %. Les limites de detection se situent entre 0,0003 et 0,003 μg.L -1 pour l'eau filtree et entre 0,01 et 0,2 μg pour les matieres en suspension.

Journal of dairy science, 2011

In a previous study, milk iodine concentration from 501 farms across Canada was found to vary con... more In a previous study, milk iodine concentration from 501 farms across Canada was found to vary considerably and appeared to be influenced by feeding practices. Farms with contrasting levels of milk iodine from a subset of 200 participating farms were used to determine the relationship between milk iodine concentration and the concentration of this mineral in different feeds and complete diets given to lactating dairy cows. The 30 farms with the lowest levels of iodine in milk (low group) and the 30 farms with the highest levels (high group) were selected. Samples of bulk tank milk, all feed ingredients, and water were collected. Additionally, each farmer completed a questionnaire providing information on feeding management. The iodine offered on each of the farms was estimated from the amount of the feed in the diet recommended by the Ration'L software (Valacta, Ste-Anne-de-Bellevue, QC, Canada) and the iodine concentration in the feed sampled and analyzed using inductively coupl...

Journal of Medicinal Chemistry, 1992

Novel 2-arylbenzimidazoles and azabenzimidazoles were synthesized, and their inotropic action was... more Novel 2-arylbenzimidazoles and azabenzimidazoles were synthesized, and their inotropic action was evaluated. Changes in left ventricular pressure, dPldt m a , were measured as an index of cardiac contractility. The structural features that impart optimal inotropic activity are presented. The most potent compounds were evaluated orally in conscious dogs with implanted Konigsberg pressure transducers. To investigate the mechanism of action, the most potent compounds were tested for their calcium-sensitizing properties and their potential for the inhibition of phosphodiesterase. Two compounds, 1 and 41, showed interesting in vitro and oral activity without side effects. They have a more potent calcium-sensitizing effect than MCI-154 and are under futher investigation. For many years cardiac glycosides have been the only available cardiotonic agents for heart failure therapy. However, for many reasons their use is limited, especially because of their arrhythmogenic liability. In the last decade, a series of nonglycosidic, nonsympathomimetic, cardiotonic agents have been developed. Amrinone1*2 and sulmazole?*' which were prototypical compounds, were followed by a second generation of more active compounds including enoximone,S16 piroximone,' ima~odan,S*~ MCI-154,10J1 indolidan,12 and pimobendanls (Figure 1). While many of the new cardiotonics appear to act by inhibition of a phosphodiesterase isozyme, resulting in an * Author to whom correspondence should be addressed.

Journal of Agricultural and Food Chemistry, 2008

Apples were sampled directly from orchard trees at 96, 45, and 21 days postapplication with one o... more Apples were sampled directly from orchard trees at 96, 45, and 21 days postapplication with one of three organophosphate insecticides (azinphos methyl, phosalone, or phosmet, respectively). Individual apples were prepared for analysis following one of three postharvest preparations: no preparation, rinsed with deionized water for 10-15 s, or rinsed and peeled. Azinphos methyl, phosalone, and phosmet concentrations ranged from below the level of detection to 5.26 ng/g, 94.7 to 5720 ng/g, and 0.011 to 663 ng/g in the apples that received no postharvest preparation, respectively. Although rinsed apples had lower maximum concentrations than observed in apples with no preparation, levels were not significantly lower. Concentrations of all three OP insecticides in apples that were rinsed followed by peeling, however, were much lower (below detection limits to 0.733 ng/g, azinphos methyl; 0.322-219 ng/g, phosalone; and below detection limits to 44.0 ng/g, phosmet) than observed in apples that had been rinsed alone. Rinsing and peeling of apples resulted in a 74.5-97.9% reduction in OP residues, while rinsing alone lowered mean concentrations by 13.5-28.7% relative to apples that received no postharvest preparation.

Journal of Agricultural and Food Chemistry, 2006

Azinphos-methyl, phosalone, and phosmet were applied individually to separate rows of trees withi... more Azinphos-methyl, phosalone, and phosmet were applied individually to separate rows of trees within a commercial apple orchard in Quebec, Canada, during the 2003 agricultural season. Apples were collected for residue analysis immediately prior to the harvesting of the remaining apples for market distribution and were prepared for analysis as both individual apples and as composites of eight individuals. Analysis of the three applied compounds, as well as five organophosphate insecticides that were not applied, was performed using gas chromatography-mass spectrometry. Azinphosmethyl, phosalone, and phosmet, which were applied, were detected in all samples analyzed at concentrations ranging from 0.004 ng/g to 2260 ng/g. Methidathion was not observed in any sample. Chlorpyrifos, diazinon, dimethoate, and malathion concentrations ranged from below method detection limits to 0.71 ng/g, and the detection frequency for these compounds ranged from 20% to 100%. Residues measured in this study were all below the Canadian maximum residue limit for apples. Variability factors ranged from 2 to 19 for all compounds observed in this study. Composite samples may not accurately reflect the extremes of exposure from consumption of single servings of apples.

Food Additives & Contaminants: Part A, 2011

Lead (Pb), cadmium (Cd) and aluminum (Al) were determined in 437 individual samples of infant for... more Lead (Pb), cadmium (Cd) and aluminum (Al) were determined in 437 individual samples of infant formulae, oral electrolytes and 5% glucose solutions available in Canada. In the electrolytes, Cd and Pb concentrations were all below 0.01 and 0.041 ng g À1 , respectively. In the 5% glucose solutions, Pb and Cd levels averaged 0.01 and 0.09 ng g À1 , respectively. Reported on an as-consumed basis, Pb levels in milk-and soya-based formulae averaged 0.90 and 1.45 ng g À1 , respectively, while Cd levels averaged 0.23 and 1.18 ng g À1 , respectively Average Al levels on an as-consumed basis were 440 ng g À1 (range 10-3400 ng g À1) in milk-based formulae and 730 ng g À1 (range 230-1100 ng g À1) in soy-based formulae. Al concentrations increased in the following order: plain formula5low-iron formula5iron-supplemented formula5casein hydrolysate formula % premature formula soy formula. For example, in the powdered formulae, average Al concentrations were 18 ng g À1 for plain milk-based, 37 ng g À1 for low-iron, 128 ng g À1 for iron supplemented, 462 ng g À1 for lactose-free, 518 ng g À1 for hypoallergenic and 619 ng g À1 for soy-based formula. Al concentrations, as-consumed, increased with decreasing levels of concentration: powder5concentrated liquid5ready-to-use. Formulae stored in glass bottles contained between 100 and 300 ng g À1 more Al than the same formulae stored in cans. The source of the increased Al did not appear to be the glass itself, because most electrolytes and glucose solutions, also stored in glass, contained less than 8 ng g À1 Al. Corresponding differences in Pb and Cd levels were not observed. Al concentrations varied substantially among manufacturers; however, all manufacturers were able to produce plain milk-based formulae containing less than 50 ng g À1 Al, i.e. within the range of Al concentrations found in human milk. Next to soya-based and hypoallergenic formulae, premature formulae contained among the highest concentrations of Al, ranging 851-909 ng g À1 from one manufacturer and 365-461 ng g À1 from another.

Food Additives and Contaminants, 2007

Apple trees in an orchard in Quebec, Canada were treated, following label directions, with the fu... more Apple trees in an orchard in Quebec, Canada were treated, following label directions, with the fungicide captan (1,2,3,6-tetrahydro-N-(trichloromethylthio)phthalimide) during the 2003 agricultural season. A total of 142 apples from three rows of trees were selected for determination of captan by GC/MS. Individual apples were found to contain captan levels ranging from 16.9 to 6350 ng g-1. Only two individual apple samples exceeded the Canadian maximum residue limit (5000 ng g-1) for captan in apples. Six composite samples, comprising half portions of eight individual apples, were analysed from each of the three experimental rows. Composite samples ranged in concentration from 166 to 2620 ng g-1. The greatest uncertainty associated with the measured concentrations was due to variability among apples rather than the measurement of residue levels.