Carbon Electrode Modified with Molecularly Imprinted Polymers for the Development of Electrochemical Sensor: Application to Pharmacy, Food Safety, Environmental Monitoring, and Biomedical Analysis

International audienceThis review aims to elucidate recent developments in electrochemical sensors that use functionalized carbon electrodes with molecularly imprinted polymers (MIPs) for the selective detection of organic compounds in diverse fields including pharmacy, food safety, environmental monitoring of pollutants, and biomedical analysis. The main targets include explosive compounds, dyes, antioxidants, disease biomarkers, pharmaceuticals, antibiotics, allergens, pesticides, and viruses. Following a brief overview of the molecular imprinting principle, the most significant applications are explored. The selection of the functional monomer is subsequently discussed. Notably, various types of carbon electrodes are presented, with a particular emphasis on screen-printed carbon electrodes. The most commonly employed techniques for MIP deposition such as electropolymerization, drop casting, and chemical grafting are introduced and discussed. Electrochemical transduction techniques like cyclic voltammetry, differential pulse voltammetry, square wave voltammetry, and electrochemical impedance spectroscopy are presented. Lastly, the review concludes by examining potential future directions and primary limitations concerning carbon electrodes modified with MIPs

Odour-active compounds of an Eisenia foetida protein powder. Identification and effect of delipidation on the odour profile

International audienceThe odour-active compounds (OAC) of an Eisenia foetida (Ef) protein powder were determined using a detection frequency gas chromatography-olfactometry method. They were isolated by a Solvent-Assisted Flavour Evaporation Extraction (SAFE) method. Sixty-eight compounds were designated as OAC, 41 of which were identified. Fifty-one percent of the identified compounds came from lipid oxidation. A Soxhlet delipidation method, with hexane, and an ultrasound extraction method, with a chloroform/methanol mixture, were used in order to dearomatize the Ef protein powder. The effect of delipidation on the OAC was studied. The Soxhlet and the ultrasound methods eliminated 70.5% and 97.7% of the OAC, respectively. The Ef protein powder was characterised by animal, chemical, earthy, floral, fruity and vegetable attributes. Soxhlet extraction reduced the vegetable and the herbaceous attributes, whereas ultrasound extraction reduced the chemical, earthy, floral, fruity and Maillard attributes

Food Protein Powder from Eisenia foetida: Dearomatization Using Food Grade Solvents and Controlled Storage Conditions

International audienceDelipidation was used to dearomatize protein powder of Eisenia foetida. The remaining volatile fraction after delipidation was studied over a period of three months. Volatile fraction dramatically increased between the first and the second month of storage. Four volatile compounds, chosen as tracers, were studied, namely: benzaldehyde, 2-pentyl furan, o-xylene, and limonene. Controlled conditions of storage are very efficient to limit volatile compound increase: 10% or less for three among the four volatile compounds chosen as tracers. The main parameter to control is temperature. To obtain a food grade protein powder, delipidation was done using ethyl acetate/ethanol instead of chloroform/methanol mixture. The remaining volatile fraction after delipidation ranged from 6% to 18%. Dearomatization was improved using an additional drying after delipidation. Solvent residues amounted to a few mg/g and conformed to EU regulations concerning solvent residues in food stuffs and food ingredients

Extraction liquide-liquide et solide-liquide des lanthanides par des b-dicétones hétérocycliques et des ligands N-donneurs,libres ou immobilisés sur des silices mésostructurées

L'extraction liquide-liquide de terres rares trivalentes Ln(III) (Ln: La, Eu, Lu), à partir de milieux aqueux nitriques, par la bis-acylpyrazolone 1,12-bis(1 -phényl-3 -méthyl-5 -hydroxy-4 -pyrazolyl)-dodecane-1,12-dione (HL-(CH2)10-LH) a été étudiée. L'extraction est d'autant plus efficace que le numéro atomique de l'élément à extraire est élevé (La < Eu < Lu). Elle se fait à plus bas pH que l'extraction par les 4-acyl-5-hydroxypyrazoles simples (HL). La présence de la 2,4,6-tri(2-pyridyl)-1,3,5-triazine, TPTZ, agent de solvatation de type 3N-donneur, provoque un effet synergique important; TPTZ impose l'ordre d'extraction synergique: La < Lu < Eu. L'extraction solide-liquide des Ln(III) par des silices mésostructurées dopées par les extractants utilisés en extraction liquide-liquide a été également étudiée. Les silices dopées ont été synthétisées à basse température selon le procédé sol-gel en utilisant les micelles de bromure de cétyltriméthylammonium, CTAB, comme agent pour structurer la porosité (synthèses de type MCM-41). Elles ont été caractérisées par porosimétrie à l'azote, diffraction des rayons X, microscopie électronique à balayage MEB, microscopie électronique à transmission MET et granulométrie laser. Les silices dopées sont déstructurées par rapport aux silices lamellaires obtenues quand le mélange synthétiquene contient pas d'extractant ; cependant, le matériau dopé conserve une grande surface spécifique (990 à 1230 m2.g-1) et reste mésoporeux. L'extraction solide-liquide par les silices dopées par HL ou HL-(CH2)10-LH est plus efficace à bas pH que l'extraction liquide-liquide ; en outre, elle est plus rapide. La stoechiométrie du complexe extrait et la capacité d'extraction de l'europium par HL-(CH2)10-LH sont comparables pour les extractions solide-liquide et micellaire. La stoechiométrie des bis-acylpyrazolonates, extraits par les trois techniques différentes, est fonction de la technique d'extraction utilisée, mais aussi des concentrations initiales des espèces chimiques dans chacune des phases. Pour l'europium, avec une silice dopée par HL-(CH2)10-LH et TPTZ, on observe une synergie d'extraction modérée. Le rapport métal/acylpyrazolonate, dans le complexe extrait par la silice dopée par HL-(CH2)10-LH seule (1:2) Eu(L-(CH2)10-L)(L-(CH2)10-LH), diffère de celui qui existe dans le complexe synergique (1:3) Eu(L-(CH2)10-LH)3(TPTZ). La capacité d'extraction de l'europium est de 0,18 mmol/g: 200 fois plus importante que celles des silices imprégnées.Liquid-liquid extraction of trivalent rare earths Ln(III) (Ln: La, Eu, Lu), from nitric aqueous media, by the bis-acylpyrazolone 1,12-bis(1'-phényl-3'-methyl-5'-hydroxy-4'-pyrazolyl)-dodecane-1,12-dione (HL-(CH2)10-LH) has been studied. The extraction occurs at lower pH than the extraction by the simple 4-acyl-5-hydroxypyrazoles (HL) and its efficiency increases with the ascending atomic number of Ln (La < Eu < Lu). The presence of a solvating agent of the type 3N-donor, 2,4,6-tri(2-pyridyl)-1,3,5-triazine, TPTZ, induces an important synergistic effect ; TPTZ governs the synergistic order of extraction : La < Lu < Eu. The solid-liquid extraction of Ln(III) by mesostructured silicas doped with the extractants used in liquid-liquid extraction has been also studied. The doped silicas were synthesized at low temperature according to the sol-gel process using cetyltrimethyl ammonium bromide, CTAB, as a templating agent for the porosity (MCM-41 type synthesis). They were characterized by BET analysis of nitrogen isotherms, X-ray diffraction, scanning electron microscopy SEM, transmission electron microscopy TEM and laser granulometry. Doped silicas are destructured compared to lamellar silicas obtained in the absence of extractant ; however, the doped material preserves high specific surface area (990 to 1230 m2.g-1) and remains mesoporous. At low pH, solid-liquid extraction by silicas doped by HL or HL-(CH2)10-LH is more efficacious than liquid-liquid extraction; moreover, it is faster. The europium extraction capacity and the stoichiometry of the complex extracted by HL-(CH2)10-LH are comparable in solid-liquid and micellar extractions. The stoichiometries of the bis-acylpyrazolonates, extracted by the three different techniques, do not only depend upon the technique of extraction used, but depend upon the initial concentrations of the chemical species in each phase too. For europium, with a silica doped by HL-(CH2)10-LH and TPTZ, a moderate extraction synergy is observed. The metal/acylpyrazolonate ratio, in the complex extracted by the silica doped by HL-(CH2)10-LH alone (1:2) Eu(L-(CH2)10-L)(L-(CH2)10-LH), differs from that existing in the synergistic complex (1:3) Eu(L-(CH2)10-LH)3(TPTZ). The europium extraction capacity found in our study is 0.18 mmol/g which is 200 times more important than those obtained with impregnated silica.STRASBOURG-Sc. et Techniques (674822102) / SudocSudocFranceF

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

Synergistic extraction of lanthanoids with heterocyclic β-ketoenols and 2,4,6-tri(2-pyridyl)-1,3,5-triazine, TPTZPart II. Extraction of La(III), Eu(III) and Lu(III) with a bis(4-acyl-5-hydroxypyrazole) and TPTZ

International audienc

Deposition routes of molecularly imprinted silica for the development of highly specific electrochemical “in-field” sensors

International audienceMolecularly imprinted silica (MIS) electrode coatings have recently returned to the center of scientific research because of their advantages over organic imprinted polymers in electro-chemical analysis. An easy-to-control and well-studied sol-gel process that uses "green solvents", rigid structure and elec-trochemical inertness of the resulting material, applicability of electrochemical deposition techniques are the key elements that make MIS attractive for targeted and sensitive electro-chemical detection. This review aims to draw attention to electrode modification using MIS. It highlights the main stra-tegies for deposing MIS films on the electrode, indicates the adjustments that need to be made to known procedures to achieve an electrochemical sensing system with the best analytical performance, and discusses the advantages and weaknesses of each deposition route

Synthesis of phosphorylated calix[4]arene derivatives for the design of solid phases immobilizing uranyl cations.

International audienceWith the aim of developing supports for uranyl cations immobilization, new 1,3-alternate calix[4]arenes bearing both phosphonic acid functions as chelating sites and N-succinimide-4-oxabutyrate as the anchoring arm were synthesized in good yields. The coupling of such calixarenes to a gel was performed and a successful immobilization of uranyl cations was obtained