Final Report Summary - DETEX (Development of a "Tandem" chemosensor system based on both highly selective and highly sensitive innovative materials: Application to ultra-trace detection of EXplosives) The objective of the DETEX research project was to demonstrate a new concept of tandem sensor presenting high sensitivity and improved selectivity. Such potentially low cost gas sensor combines and integrates a highly selective material such as a Molecularly imprinted polymer (MIP) and a highly sensitive transducer such as an amplifying fluorescent polymer. The ultimate goal of this project was to open the way to an alternative route to classical standards for gas detection and analysis through the implementation of an advanced and innovative concept strongly relying on the design and optimisation of specifically engineered functional materials. Tasks required for the demonstration of the DETEX concept were organised in six work packages (WPs) covering different areas, from synthetic chemistry through device physics, to device fabrication. The structure of the work plan was as follows: - WP 1: Design and synthesis of selective, sensitive materials (MIPs). This first WP was devoted to the design and optimisation of a filter able to bind selectively nitroaromatic compounds from standard TNT explosives (2,4-dinitrotoluene, 1,3-dinitrobenzene) and to pre-concentrate vapours prior to detection. This filter was based on a polymer presenting molecular recognition abilities obtained by molecular imprinting techniques. - WP 2: Design, synthesis and basic characterisations of fluorescent transducing polymers. This work package concerned the design and the synthesis of amplifying fluorescent polymers having a high stability to temperature and / or solvents. Two types of fluorescent polymers were developed within this WP: p-conjugated polymers having selective receptors incorporated into side chains or into the polymer backbone, and copolymers bearing fluorescent entities and binding groups in their side chains. - WP 3: Physico-chemical characterisation of materials. This work package was dedicated to the physico-chemical characterisation of the materials coming either from WPs 1 and 2 (fluorescent and molecularly imprinted polymers). The main objective of this WP was to evaluate structure-property relationships in order to optimise and validate WP1 and WP2 synthetic protocols. - WP 4: System design and integration. Objectives of this WP were the specification, the design and the fabrication of the tandem chemosensor system. - WP 5: Sensor performances testing. This WP was devoted to advanced characterisations and tests of the tandem chemosensor system performances in terms of selectivity, sensitivity, reproducibility and response time. Objectives of this WP were also to identify potentially interfering analytes which could lead to false alarms, to prepare test samples and to evaluate and optimize the measurement uncertainty. - WP 6: Industrialisability assessment. This WP was mainly concerned with the industrialisability of a new trace detector of explosives. Accomplishing this task would be done through: A market analysis, allowing an accurate evaluation of the needs in the field of security, the development of contacts with potential end-users and the definition of sensor manufacturing technologies. - WP 7: Management and coordination activities. The main expected achievements of the project were: - the synthesis of MIP filters showing high selectivity and affinity for nitroaromatic target compounds; - the successful synthesis of fluorescent transducer showing high sensitivity to nitroaromatics and good stability; - the realisation of a test device sensor for nitroaromatics working in the gas phase; - the evaluation of the performance of the system in terms of sensibility and selectivity. A sensitivity better than 0,01 ppm for 2,4 DNT, no sensitivity for interferents such as perfumes, a response time lower than a few minutes would be considered as a minimum objective. There were two exploitable results that were publishable at the end of the DETEX project: - a new concept of chemosensor: the tandem sensor system. This exploitable result refers to a new concept of chemical sensors for the detection of vapour traces of molecules such as explosives or drugs. In this new sensor system, a highly sensitive light emitting polymer is associated to a highly selective sorbant, capable of preconcentrating and filtering vapour molecules prior to their detection by the amplifying fluorescent material. This original concept would allow the detection of ultra-trace amounts of chemical substances with a reduced number of false alarms. - method for preparing a hybrid organic-inorganic sorbants for the recognition of nitroaromatic compounds. This exploitable result covers a method of preparation of selective sorbants that can be used for the separation, extraction and detection of chemical substances containing electro-attractive units such as for 2,4-dinitrotoluene or 1,3-dinitrobenzene. Related documents Final Report - DETEX (Development of a "Tandem" chemosensor system based on both highly selective and highly sensitive innovative materials: Application to ultra-trace detection of EXplosives)
