The aim of this project is to develop new concentration membranes based on immunology in the analysis of low concentrations of pesticides.
Pesticides are usually analyzed either by gas chromatography or by liquid chromatography. However, their determinations in environmental samples are impossible by direct injection, because samples are too dilute and too complex. A pre-concentration step is required and is usually carried out by liquid/liquid or liquid/solid extractions. These methods are time-consuming and non selective, so that low-level determinations (< 0,1 mlg/l) are very difficult to be obtained because many other compounds from the sample matrix are also concentrated and interfere in the analysis. An antibody against a series of pesticides is covalently bound to a membrane. The sample is percolated through the cartridge constructed with these membranes. The pesticides and related conversion products are pinpointed by the membrane whereas the other molecules are not retained on it. Therefore, the antibody will be used only as a specific trap for the concentration of molecules of interest. Then, the pesticides will be eluted by an appropriate mean (salt gradient for instance) prior to their separation and analysis by liquid chromatography. This method will allow an individual and- quantitative-analysis for each compound of the mixture, in contrast to immunoassay-method.
The advantages of this project are numerous: 1) concentration of pesticides and of both hydrophilic and hydrophobic related conversion products allowing very simple determination at low levels; 2) the separation of the concentrated pesticides can be expected by a selective elution; 3) better knowledge of the transport and fate of pesticides in the environment.
Three widely used groups of pesticides have been selected for this study: chlorotriazines, phenylureas and aryloxyacid herbicides.
Funding SchemeCSC - Cost-sharing contracts