Reference : UMR8531-CEDMON-003
Workplace : GIF SUR YVETTE
Date of publication : Wednesday, September 14, 2022
Type of Contract : FTC Scientist
Contract Period : 12 months
Expected date of employment : 1 November 2022
Proportion of work : Full time
Remuneration : from 3018€ to 3897€ gross monthly depending on experience
Desired level of education : PhD
Experience required : Indifferent
The objective of the project is to provide a sensitive (according to EU and WHO requirements) and selective detection method for atrazine, while being simple and usable by non-expert users.
In order to provide such characteristics, we envisage the exploitation of a molecular recognition unit grafted on Quantum Dots and incorporated in microfluidic channels. The main objectives of this project are decomposed into four Tasks, each one being partially independent. This Postdoctoral offer will focus on the first two tasks:
- Task 1 - Synthesis of the supramolecular recognition unit:
Molecular design supported by a theoretical study (DFT) is performed before the postdoctoral contract in order to select the molecular structures presenting the best affinity with atrazine. The synthesis (classical organic chemistry techniques, microwave chemistry, organometallic catalysis) and the characterization (NMR, IR, HPLC, mass, UV-Visible and emission spectroscopy) of the molecular probes will be the missions of this position. Once the molecular probes are synthesized and characterized, complexation studies with Atrazine(titration, determination of association constant) will be performed in solution. The detection will be carried out preferably by spectroscopic techniques.
- Task 2 - Preparation and study of Quantum Dots :
Quantum Dots (QDs) are widely used as photoluminescent probes because their properties are easily controllable and they are not subject to photobleaching. The second task of this position will therefore be the preparation of Quantum Dots via methods already in place in the laboratory (hot injection) and then to functionalize them with the recognition entity prepared during Task 1. The two tasks can progress in parallel and meet at the time of grafting. Once the nano-objects are obtained, they will also be characterized using spectroscopic techniques (UV-visible, emission, transient absorption, lifetime), microscopies (SEM, TEM) or DLS, Nanosight and Zetameter. Their recognition property towards atrazine will then be evaluated in solution and on surface (sensitivity, determination of detection limit, fatigue resistance, recyclability...).
- Synthesis of molecular receptors (dibenzanthracene derivatives) for atrazine
- Physicochemical characterization of these molecules (structure, spectroscopy, complexation...)
- Synthesis and functionalization of metal chalcogenide quantum dots (CdS, CdSe, PbS)
- Studies of nano-objects in solution and deposited on surface (microscopy, spectroscopy, molecular recognition...)
- Participation in the writing of scientific articles in peer-reviewed journals
- Participation in national and international conferences (oral communication and/or poster)
- Participation in the life and organization of the laboratory (management of stocks and waste, maintenance of equipment)
We are looking for a motivated candidate with a PhD in Physical Chemistry or Organic Chemistry and familiar with spectroscopy and fluorescence techniques. He/she should also have a taste for organic synthesis and supramolecular chemistry. Expected skills:
- Competence in multi-step organic synthesis
- Competence in deaerated anhydrous synthesis (Schlenk technique)
- Competence in separative techniques (chromatography, HPLC...)
- Expertise in 1H and 13C NMR
- Skills in stationary and time-resolved spectroscopy
- Knowledge and interest in environmental chemistry
- Knowledge and interest in supramolecular chemistry
- Knowledge and interest in quantum dot chemistry
- Ability to keep a laboratory notebook in a rigorous manner
- Good interpersonal skills and ability to integrate into the host group as well as with the other academic partners of the project.
- Writing skills in French and/or English, as well as the ability to present work to different audiences
- Proficiency in English at C2 level according to the Common European Framework of Reference for Languages
This postdoctoral position is part of the ASTRID project funded by the ANR (ANR-21-CE04-0001). This project aims to develop, in collaboration, microfluidic systems dedicated to the detection and quantification of s-triazine derived herbicides (e.g. Atrazine). The unique photophysical properties of the semiconductor nanocrystals and the selective recognition unit combined inside microfluidic chips will allow highly sensitive and specific detection of s-triazine derivatives at the ppb level by spectroscopic techniques. This device will provide alternative tools for direct and field detection/quantification of herbicide pollutants in soil, water and consumer products.
This work will be carried out within the PPSM laboratory, a chemistry and spectroscopy laboratory within the ENS Paris-Saclay and the Université Paris-Saclay. Its activities are focused on the research and study of molecules and materials that can be stimulated by photo-induced phenomena, by the action of electrons or by the presence of ions, molecules and biological activity.
This group is integrated into the problems related to the environment, health and information technologies. In this context, the material resources and skills of the different chemistry specialties are brought together in PPSM, which allows several facets of a chemist's work to be carried out: design (molecular engineering), synthesis of molecules, manufacture of materials or devices and study of properties.
The members of PPSM are present in the scientific community on a national and international scale, contributing to the advancement of fundamental knowledge: photochemistry, fluorescence, spectroscopy, electrochemistry, nanomaterials, molecular recognition.
The PPSM is a member of the Institut d'ALEMBERT (FR3242) and leads the GdR Photo Electro Stimulation (PES) and the LIA Nano-Synergetics.
The PPSM is also a member of the initiative of excellence (IdEx) campus Paris-Saclay and of two laboratories of excellence: LabEx NanoSaclay and LabEx Charmmmat.
Constraints and risks
Risks related to the handling of chemicals.
Risks related to the handling of nanoparticles.
Handling in ventilated fume cupboards in accordance with current standards.
Risks related to the use of the NMR spectrometer (magnet).
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