13 research outputs found
Design d'un iprodione-MIP (molecularly imprinted polymer) : application à la pré-concentration des fongicides dans le vin
The aim of this study was the synthesis of a MIP (molecularly imprinted polymer) specific for a fungicide that is found in the majority of the french wine: iprodione. The challenge for extracting iprodione from wine medium was that the hydoralcoholic solution is a dipolar solvent, whereas the interaction between the MIP and iprodione is based on dipolar interactions. The first extraction study of iprodione was made on a MIP synthesized by bulk polymerization using methacrylamide and ethylene glycol dimethacrylate (EGDMA). The MIP was found to be more efficient than the NIP (non-imprinted polymer) in hydroalcoholic solutions which demonstrates that the molecular imprinting was successful. Then we synthesized 8 MIPs and 8 NIPs following an 23 experimental design in order to study the influence of three synthesis factors (the polymerization method, the nature of the crosslinker and the type of the functional monomer) on the iprodione recognition properties of the polymers. The water and the iprodione adsorption isotherms for MIPs and NIPs were determined. The result showed significant differences between the polymers involving a relationship between the water adsorption and the adsorption of iprodione. The molecular imprinting has been demonstrated by several techniques such as the differential scanning calorimetry and the nuclear magnetic resonance. The best recognition properties of iprodione are obtained with the MIP which was synthesized by precipitation polymerization using methacrylamide as functional momonomer and EGDMA as crosslinker. This MIP was used in solid phase extraction (SPE) for pre-concentration of iprodione in a white wine with a pre-concentration factor of 6. Its selectivity versus two fungicides: procymidone and pyrimethanil has been demonstrated.Les travaux de thĂšse ont portĂ© sur la synthĂšse dâun MIP (polymĂšre Ă empreintes molĂ©culaires) spĂ©cifique dâun fongicide se trouvant dans la majoritĂ© des vins français : lâiprodione. Pour extraire lâiprodione Ă partir du vin, un challenge important se prĂ©sentait : le milieu hydroalcoolique est un solvant dipolaire alors que lâinteraction du MIP avec lâiprodione se base sur des interactions dipĂŽle-dipĂŽle. Les premiĂšres Ă©tudes dâextraction de lâiprodione ont Ă©tĂ© faites sur un MIP obtenu par polymĂ©risation en masse Ă partir du mĂ©thacrylamide et de l'Ă©thylĂšne glycol dimĂ©thacrylate (EGDMA). Le MIP Ă©tait plus efficace que le NIP (polymĂšre non imprimĂ©) dans des solutions hydroalcooliques ce qui vĂ©rifie que lâimpression molĂ©culaire Ă©tait rĂ©ussie. Un plan dâexpĂ©riences 23 a Ă©tĂ© appliquĂ© pour Ă©tudier lâinfluence de 3 facteurs de synthĂšse de MIP (la mĂ©thode de polymĂ©risation, la nature de l'agent rĂ©ticulant et le type de monomĂšre fonctionnel) sur les propriĂ©tĂ©s de reconnaissance des polymĂšres vis-Ă -vis de lâiprodione. 8 MIP et 8 NIP ont Ă©tĂ© ainsi synthĂ©tisĂ©s. Les isothermes d'adsorption de l'eau et de lâiprodione par les MIPs et les NIPs ont Ă©tĂ© dĂ©terminĂ©es. Des diffĂ©rences significatives entre les polymĂšres ont Ă©tĂ© mises en Ă©vidences impliquant une relation entre lâadsorption de lâeau et lâadsorption de lâiprodione. La formation des empreintes molĂ©culaires au sein des MIP a Ă©tĂ© dĂ©montrĂ©e par plusieurs techniques comme la calorimĂ©trie diffĂ©rentielle Ă balayage et la rĂ©sonance magnĂ©tique nuclĂ©aire. Les meilleures propriĂ©tĂ©s de reconnaissance de lâiprodione sont obtenues avec le MIP synthĂ©tisĂ© par prĂ©cipitation Ă partir du mĂ©thacrylamide comme monomĂšre fonctionnel et de lâEGDMA comme rĂ©ticulant. Ce MIP a Ă©tĂ© utilisĂ© en extraction en phase solide (SPE) pour la prĂ©-concentration de lâiprodione dans un vin blanc avec un facteur de prĂ©-concentration Ă©gal Ă 6 et sa sĂ©lectivitĂ© par rapport Ă deux fongicides : le pyrimĂ©thanil et le procymidone a Ă©tĂ© dĂ©montrĂ©e
Design of an iprodione-MIP (molecularly imprinted polymer) : application to the preconcentration of fungicides in wine
Les travaux de thĂšse ont portĂ© sur la synthĂšse dâun MIP (polymĂšre Ă empreintes molĂ©culaires) spĂ©cifique dâun fongicide se trouvant dans la majoritĂ© des vins français : lâiprodione. Pour extraire lâiprodione Ă partir du vin, un challenge important se prĂ©sentait : le milieu hydroalcoolique est un solvant dipolaire alors que lâinteraction du MIP avec lâiprodione se base sur des interactions dipĂŽle-dipĂŽle. Les premiĂšres Ă©tudes dâextraction de lâiprodione ont Ă©tĂ© faites sur un MIP obtenu par polymĂ©risation en masse Ă partir du mĂ©thacrylamide et de l'Ă©thylĂšne glycol dimĂ©thacrylate (EGDMA). Le MIP Ă©tait plus efficace que le NIP (polymĂšre non imprimĂ©) dans des solutions hydroalcooliques ce qui vĂ©rifie que lâimpression molĂ©culaire Ă©tait rĂ©ussie. Un plan dâexpĂ©riences 23 a Ă©tĂ© appliquĂ© pour Ă©tudier lâinfluence de 3 facteurs de synthĂšse de MIP (la mĂ©thode de polymĂ©risation, la nature de l'agent rĂ©ticulant et le type de monomĂšre fonctionnel) sur les propriĂ©tĂ©s de reconnaissance des polymĂšres vis-Ă -vis de lâiprodione. 8 MIP et 8 NIP ont Ă©tĂ© ainsi synthĂ©tisĂ©s. Les isothermes d'adsorption de l'eau et de lâiprodione par les MIPs et les NIPs ont Ă©tĂ© dĂ©terminĂ©es. Des diffĂ©rences significatives entre les polymĂšres ont Ă©tĂ© mises en Ă©vidences impliquant une relation entre lâadsorption de lâeau et lâadsorption de lâiprodione. La formation des empreintes molĂ©culaires au sein des MIP a Ă©tĂ© dĂ©montrĂ©e par plusieurs techniques comme la calorimĂ©trie diffĂ©rentielle Ă balayage et la rĂ©sonance magnĂ©tique nuclĂ©aire. Les meilleures propriĂ©tĂ©s de reconnaissance de lâiprodione sont obtenues avec le MIP synthĂ©tisĂ© par prĂ©cipitation Ă partir du mĂ©thacrylamide comme monomĂšre fonctionnel et de lâEGDMA comme rĂ©ticulant. Ce MIP a Ă©tĂ© utilisĂ© en extraction en phase solide (SPE) pour la prĂ©-concentration de lâiprodione dans un vin blanc avec un facteur de prĂ©-concentration Ă©gal Ă 6 et sa sĂ©lectivitĂ© par rapport Ă deux fongicides : le pyrimĂ©thanil et le procymidone a Ă©tĂ© dĂ©montrĂ©e.The aim of this study was the synthesis of a MIP (molecularly imprinted polymer) specific for a fungicide that is found in the majority of the french wine: iprodione. The challenge for extracting iprodione from wine medium was that the hydoralcoholic solution is a dipolar solvent, whereas the interaction between the MIP and iprodione is based on dipolar interactions. The first extraction study of iprodione was made on a MIP synthesized by bulk polymerization using methacrylamide and ethylene glycol dimethacrylate (EGDMA). The MIP was found to be more efficient than the NIP (non-imprinted polymer) in hydroalcoholic solutions which demonstrates that the molecular imprinting was successful. Then we synthesized 8 MIPs and 8 NIPs following an 23 experimental design in order to study the influence of three synthesis factors (the polymerization method, the nature of the crosslinker and the type of the functional monomer) on the iprodione recognition properties of the polymers. The water and the iprodione adsorption isotherms for MIPs and NIPs were determined. The result showed significant differences between the polymers involving a relationship between the water adsorption and the adsorption of iprodione. The molecular imprinting has been demonstrated by several techniques such as the differential scanning calorimetry and the nuclear magnetic resonance. The best recognition properties of iprodione are obtained with the MIP which was synthesized by precipitation polymerization using methacrylamide as functional momonomer and EGDMA as crosslinker. This MIP was used in solid phase extraction (SPE) for pre-concentration of iprodione in a white wine with a pre-concentration factor of 6. Its selectivity versus two fungicides: procymidone and pyrimethanil has been demonstrated
Molecularly imprinted polymers for the removal of Iprodione from wine : experimental design and synthesis optimization
International audienceSubstantial evidence demonstrates the potential for transfer of fungicides during the winemaking process. In order to remove these fungicides from wine samples, molecularly imprinted polymers (MIP) have been prepared and tested in a hydro-alcoholic solution containing Iprodione. Iprodione was chosen as fungicide because it was detected in more than 90 % of the French wine according to a survey done by the French ministry of agriculture
Utilisation d'un polymÚre à Empreintes Moléculaires pour piéger l'iprodione en milieu aqueux
Molecularly imprinted sol-gel polymers for the analysis of iprodione fungicide in wine: Synthesis in green solvent
International audienceIprodione is a fungicide widely used in viticulture in most agricultural countries. It was banned recently in the European community because of its carcinogenic and endocrine disrupting characters. In this work, a cheap analytical method able to monitor iprodione in a white wine was developed. Molecularly imprinted sol-gel polymers (MIS) specific to iprodione and using green solvents were synthesized. An experimental design having the following factors (solvent volume and crosslinker quantity) was used to prepare an optimal MIS. In terms of selectivity, the optimal MIS showed the best partition coefficient towards iprodione in a white wine containing four other competing fungicides (procymidone, pyrimethanil, azoxystrobin and iprovalicarb). A solid phase extraction method using the optimal MIS was optimized and applied to analyse iprodione in a white wine. Low detection and quantification limits were reached 11.7 and 39.1âŻÂ”g/L respectively
Comparison of molecularly imprinted polymers (MIP) and solâgel molecularly imprinted silica (MIS) for fungicide in a hydro alcoholic solution
International audienceThe aim of this work was (i) to design the best molecularly imprinted silica (MIS) specific for iprodione, a fungicide polluting water, fruits, wine and (ii) to compare the performance of the optimal MIS with its analogue molecularly imprinted polymer (MIP), with the objective to obtained the highest imprinting factor possible. Iprodione was widely used in viticulture. It was recently banned by the European community because of its carcinogenic potential and its presence in or on foods.The binding capacity performance of these polymers was investigated using batch binding studies in hydro alcoholic solutions (10 and 50 %). Langmuir, Freundlich and Temkin models have been used to fit adsorption isotherms. The optimal MIS was obtained using APTMS as functional monomer, low solvent solventvolume and high cross linker quantity during its synthesis. Increasing the quantity of crosslinker and decreasing the solvent volume during the MIS synthesis enhanced the imprinting factor and the binding capacity.The optimal MIS had a higher imprinting factor but a lower binding capacity than the optimal MIP specific to iprodione. The imprinting factor of the optimal MIS was 135 times higher than the optimal MIP. Unlike MIP, MIS kept its molecular recognition nature even under extremely polar media such as the aqueous sample
Experimental design approach in the synthesis of molecularly imprinted polymers specific for iprodione fungicide
International audienceAn experimental design (ED) approach was applied to study the weight of three factors in the synthesis of a molecularly imprinted polymer (MIP) specific for iprodione fungicide. The objective was to obtain a high specific polymer with the best performance of iprodione binding. Thirteen iprodione-imprinted polymers and 13 non-imprinted polymers (NIP) were synthesized according to ED having 3 influencing factors: the polymerization method, the crosslinker nature and the functional monomer type. For each factor, two levels were studied: bulk and precipitation polymerization for the first factor, trimethylolpropane trimethacrylate (TRIM) and ethylene glycol dimethacrylate (EGDMA) for the second factor, and methacrylamide (MAM) alone or with styrene for the third factor. The ED responses were: the imprinting factor, the site number and the apparent affinity constant. They were determined after studying the interactions between iprodione and each MIP and NIP in hydro-alcoholic medium. The best polymer of the ED was synthesized using MAM as functional monomer, EGDMA as crosslinker and precipitation polymerization. It has an imprinting factor of 2.4, a site number of 1172 and an affinity constant of 19.36. The best MIP was characterized by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Nitrogen sorption isotherms. The best MIP has a mesoporous structure with a high specific surface area of 407 m(2).g(-1). Molecularly imprinted solid phase extraction (MISPE) was successfully applied, using the best MIP, to preconcentrate iprodione from a white wine containing two competing fungicides. (C) 2015 Elsevier B.V. All rights reserved
Water sorption isotherms of molecularly imprinted polymers. Relation between water binding and iprodione binding capacity
International audienceMolecularly imprinted polymers are often used in aqueous medium in order to recognize specifically a target molecule. The molecular recognition is usually based on hydrogen bonding. In this case, water molecule presents a serious competition towards the target molecule. In this study, the water sorption by molecularly imprinted polymers was studied in aqueous medium. The molecularly imprinted polymers were specific for iprodione fungicide and were prepared using a 24 full factorial experimental design. They were synthesized using EGDMA or TRIM as crosslinker, methacrylamide or styrene as functional monomer and using bulk or precipitation polymerization. The water sorption isotherms were established in a range of water activities 0.05â0.90 at 25 °C. The kinetics of water sorption by the polymers were modeled using Peleg's equation. This model shows that polymers having the highest water sorption capacities have high values of imprinting factor. The GuggenheimâAndersonâde Boer isotherm equations were used to fit the equilibrium data and the corresponding parameters were calculated. This model shows that polymers synthesized with EGDMA have higher water sorption capacities than those synthesized with TRIM due to the higher hydrophobicity of the latter. Peleg and GuggenheimâAndersonâde Boer equations satisfactorily modeled the water sorption on the imprinted and non-imprinted polymers. The results obtained from both equations were practically coincident. Principal component analysis was used as a chemometric tool in order to demonstrate that a polymer having a low adsorption energy and a high capacity of water retention could be applied to extract a target molecule from aqueous media
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GATA5 mutation homozygosity linked to a double outlet right ventricle phenotype in a Lebanese patient
Abstract Background: GATA transcription factors are evolutionary conserved zinc finger proteins with multiple roles in cell differentiation/proliferation and organogenesis. GATA5 is only transiently expressed in the embryonic heart, and the inactivation of both Gata5 alleles results in a partially penetrant bicuspid aortic valve (BAV) phenotype in mice. We hypothesized that only biallelic mutations in GATA5 could be disease causing. Methods: A total of 185 patients with different forms of congenital heart disease (CHD) were screened along 150 healthy individuals for GATA4, 5, and 6. All patients' phenotypes were diagnosed with echocardiography. Results: Sequencing results revealed eight missense variants (three of which are novel) in cases with various conotruncal and septal defects. Out of these, two were inherited in recessive forms: the p.T67P variant, which was found both in patients and in healthy individuals, and the previously described p.Y142H variant which was only found in a patient with a double outlet right ventricle (DORV). We characterized the p.Y142H variant and showed that it significantly reduced the transcriptional activity of the protein over cardiac promoters by 30â40%. Conclusion: Our results do prove that p.Y142H is associated with DORV and suggests including GATA5 as a potential gene to be screened in patients with this phenotype
Sensory Motor Function Disturbances in Mice Prenatally Exposed to Low Dose of Ethanol: A Neurobehavioral Study in Postnatal and Adult Stages
Prenatal alcohol exposure (PAE) refers to fetal exposure to alcohol during pregnancy through placental barrier transfer from maternal blood. The postnatal outcomes of PAE differ among exposed individuals and range from overt (serious) alcohol-related behavioral and neurophysiological impairments to covert (silenced) symptoms. The aims of the present investigation were to assess the postnatal neurobehavioral disturbances, particularly, motor coordination and sensory-motor function in mice with PAE. Female mice with positive vaginal plugs were divided into three groups: group 1: Et + Pyr: received two i.p injections of ethanol (1 g/kg) followed by pyrazole (100 mg/kg). Group 2: Pyr: received an i.p injection of pyrazole (100 mg/kg). Group 3: C: of saline controls received, in equal volume, saline solution (NaCl 0.9%). After birth, mice pups were weighed and subjected to behavioral tests for motor function screening using the motor ambulation test, cliff aversion, surface righting, and negative geotaxis, while at the adult stage, mice were subjected to the open field, rotarod, parallel bars, and static rods tests. Our data show an obvious decrement of body weight from the first post-natal day (P1) and continues over the adult stage. This was accompanied by an obvious impaired sensory-motor function which was maintained even at the adult stage with alteration of the locomotor and coordination abilities. The current data demonstrate the powerful neurotoxic effect of prenatal ethanol exposure on the sensory-motor and coordination functions, leading to suppose possible structural and/or functional neuronal disturbances, particularly the locomotor network