An easy-to-use colorimetric enzymatic test-system for organophosphorus insecticides detection in olive oil

International audienceImmobilization of a low amount of electric eel acetylcholinesterase on microtiter plates by bioencapsulation in a sol-gel composite led to the preparation of a simple colorimetric enzymatic-assay for pesticides detection in olive oil. This bioassay has been used to carry out inhibition studies with three pesticides mainly used in the treatment of olive trees: Malaoxon, Methidathion-oxon and Omethoate, and tested using standard solutions and real samples of olive oil. The developed bio-tools showed a good reproducibility and stability as well as good analytical performances with limits of detection at least 10 times less than the maximum residue limit tolerated by international regulations. The obtained LODs were as low as 10-9 M for the widely used pesticide Malaoxon, 10-8 M for Methidathion oxon and 10-7 M for Omethoate. The developed test was designed for fast detection of the three target insecticides in such a complex matrix as olive oil without a laborious pre-treatment and after a simple liquid-liquid extraction, which demonstrate the potentiality of this technique to be used for commercial purpose

Enzymatic biosensor associated with Molecularly Imprinted Polymers for sensitive and selective detection of organophosphorus insecticides in olive oil

International audience5 different bio-tools have been developed for sensitive detection of three organophosphorus insecticides mainly used for the treatment of olive trees: Malaoxon, Omethoate and Methidathion-oxon. The systems are based on the immobilization of electric eel acetylcholinesterase on screen-printed electrode (SPE) and microtiter plates by 3 different methods of immobilization. These developed systems were optimized with laboratory samples and then tested on natural samples of olive oil after a simple liquid-liquid extraction. Among these five systems designed, the amperometric biosensor based on acetylcholinesterase immobilized by bioencapsulation in a sol-gel matrix presented the best performance in terms of operational stability, storage stability, reproducibility, and it proved to be best suited for the determination of insecticides in real samples of olive oil. This biosensor has been associated with a highly selective extraction method based on the use of Molecularly Imprinted Polymers (MIPs) to improve selectivity. The results showed that the association MIPs-biosensor can selectively detect and quantify the three organophosphorus insecticides in such a complex matrix as olive oil, with limits of detection much lower than the maximum residue limit tolerated by international regulations

Pharmaceuticals released from senior residences: occurrence and risk evaluation

One of the main pursuits, yet most difficult, in monitoring studies is to identify the sources of environmental pollution. In this study, we have identified health-care facilities from south European countries as an important source of pharmaceuticals in the environment. We have estimated that compounds consumed in by the elderly and released from effluents of senior residences can reach river waters at a concentration higher than 0.01 μg/L, which is the European Medicines Agency (EMA) threshold for risk evaluation of pharmaceuticals in surface waters. This study has been based on five health institutions in Portugal, Spain, and France, with 52 to 130 beds. We have compiled the pharmaceuticals dispensed on a daily base and calculated the consumption rates. From 54.9 to 1801 g of pharmaceuticals are consumed daily, with laxatives, analgesics, antiepileptics, antibiotics, and antidiabetic agents being the main drug families administered. According to excretion rates, dilution in the sewerage system, and elimination in wastewater treatment plants, macrogol, metformin, paracetamol, acetylcysteine, amoxicillin, and gabapentin, among others, are expected to reach river waters. Finally, we discuss the risk management actions related to the discharge of pharmaceuticals from senior residences to surface waters

Detection of Salmonella in Food Matrices, from Conventional Methods to Recent Aptamer-Sensing Technologies

International audienceRapid detection of the foodborne pathogen Salmonella in food processing is of crucial importance to prevent food outbreaks and to ensure consumer safety. Detection and quantification of Salmonella species in food samples is routinely performed using conventional culture-based techniques, which are labor intensive, involve well-trained personnel, and are unsuitable for on-site and high-throughput analysis. To overcome these drawbacks, many research teams have developed alternative methods like biosensors, and more particularly aptasensors, were a nucleic acid is used as biorecognition element. The increasing interest in these devices is related to their high specificity, convenience, and relative rapid response. This review aims to present the advances made in these last years in the development of biosensors for the detection and the quantification of Salmonella, highlighting applications on meat from the chicken food chain

Biocapteur associant l acétylcholinestérase et la phosphotriesterase pour un contrôle environnemental des insecticides organophosphorés

PERPIGNAN-BU Sciences (661362101) / SudocSudocFranceF

Monoclonal Antibody-Based Immunosensor for the Electrochemical Detection of Chlortoluron Herbicide in Groundwaters

Chlortoluron (3-(3-chloro-p-tolyl)-1,1-dimethyl urea) is an herbicide widely used in substitution to isoproturon to control grass weed in wheat and barley crops. Chlortoluron has been detected in groundwaters for more than 20 years; and dramatic increases in concentrations are observed after intense rain outbreaks. In this context; we developed an immunosensor for the determination of chlortoluron based on competitive binding of specific monoclonal antibodies on chlortoluron and immobilized biotinylated chlortoluron; followed by electrochemical detection on screen-printed carbon electrodes. The optimized immunosensor exhibited a logarithmic response in the range 0.01–10 µg·L−1; with a calculated detection limit (LOD) of 22.4 ng·L−1; which is below the maximum levels allowed by the legislation (0.1 µg·L−1). The immunosensor was used for the determination of chlortoluron in natural groundwaters, showing the absence of matrix effects

Biocapteurs à déshydrogénases pour le contrôle des aliments et de l environnement

Les déshydrogénases NAD-dépendantes constituent une classe d enzymes particulièrement attractives pour le dosage de nombreux substrats dans le domaine agro-alimentaire, et en particulier dans le secteur viti-vinicole. Cette thèse de doctorat décrit la mise au point de biocapteurs ampérométriques pour le contrôle de la fermentation malolactique du vin. Les différents capteurs développés sont basés sur des systèmes bi-enzymatiques couplant la malate déshydrogénase (MDH) à une NADH oxydase, ou sur des systèmes mono-enzymatiques associant la MDH ou une malate-quinone oxydoréductase (MQO) à des médiateurs électroniques judicieusement sélectionnés. Des capteurs utilisant une aldéhyde déshydrogénase ont été également décrits pour la détection de fongicides et fumigants de la famille chimique des dithiocarbamatesNAD-dependent dehydrogenases constitute a particularly attractive class of enzymes for the determination of various substrates in agrifood industry, and more specifically for wine industry. This thesis describes the development of amperometric biosensors for the monitoring of malo-lactic fermentation of wine. The different sensors designed are based either on bi-enzymatic systems coupling malate dehydrogenase (MDH) and NADH oxidase, or on mono-enzymatic systems associating MDH or a malate-quinone-oxidoreductase (MQO) with suitable electronic mediators.Sensors incorporating an aldehyde dehydrogenase are also described for the detection of dithiocarbamate fungicides and fumigantsPERPIGNAN-BU Sciences (661362101) / SudocSudocFranceF