TIME TRAVEL IS EASY MODELING, METHODOLOGY Nanoparticle synthesis is a very active field of research for the preparation of AND INSTRUMENTATION materials that are relevant to energy conversion, environmental remediation SYNCHROTRON SOLEIL HIGHLIGHTS 2020 or information storage. The precise control of their composition, shape and size requires a detailed understanding of their synthesis pathway. X-ray absorption spectroscopy provides such information, since it MICROFLUIDICS allows determining the oxidation states and local structure of virtually LABORATORY, LUCIA, any element. This technique is, however, very challenging to apply to fast reactions, because of the time required to obtain data with a good PROXIMA-1 & SWING signal-to-noise ratio. Using a microfluidic mixer, it is possible to create a BEAMLINES liquid-liquid interface, where a nanoparticle synthesis reaction occurs [4]. By moving a micron-sized X-ray beam along this interface, it is possible Associated publication to access different points in time along the reaction, whitout using a time-resolved spectroscopic technique. This time-space conversion The microfluidic laboratory therefore allows observing nanoparticles formation under synthetic at Synchrotron SOLEIL. conditions. The LUCIA team has performed such an experiment, where I. Chaussavoine, A. Beauvois, T. Mateo, they studied the synthesis of iron (oxy)hydroxide nanoparticles that are R. Vasireddi, N. Douri, J. Priam, relevant to heavy metal trapping and transport in natural environments Y. Liatimi, S. Lefrançois, H. Tabuteau, (Figure 2) [5]. Similar time-resolved experiments were also performed on M. Davranche, T. Bizien, D. Vantelon, the SWING beamline, where small/wide angle X-ray scatterring was used L. M. G. Chavas, B. Lassalle-Kaiser. to observe protein conformational changes or nanoparticles evolution. Journal of Synchrotron Radiation, FIGURE 2 27, 230 (2020). References [1] G. M. Whitesides, Nature, 442, 368 (2006). [2] M. Mazzorana et al., Drug Discov. Today Technol. doi.org/10.1016/j. ddtec.2020.10.003 (2020). [3] J. Kern, et al., Nature, 563, 421 (2018). [4] E. Chan et al., J. Phys. Chem. A, 111, 12210 (2007). [5] D. A. Dzombak et al., Surface Complexation Modelling: Hydrous Ferric Oxide; John Wiley & Sons, 1990. Corresponding author WHERE DOES IT STOP? Benedikt Lassalle-Kaiser The handling of suspended objects and the control of interfaces open the Synchrotron SOLEIL, Saint-Aubin, 91192 Gif-sur-Yvette, France field to a wide range of synchrotron-based experiments, where samples benedikt.lassalle@ can be studied in conditions as close as possible to those under which synchrotron-soleil.fr they function. X-ray crystallogapy,small/wide angle X-ray scatterring or X-ray absorption spectroscopy can provide crucial information on Captions samples under in cellulo/in situ conditions. Combined with off-line FIGURE 1: Microfluidic chip (a) with details of analysis techniques (such as visible or electronic microscopy), microfluidic microcrystals trapped (b) in it. View of the chip installed sample environments can hold a central place in an integrative research on the goniometer of PROXIMA-1 for an in situ diffaction workflow. As for future developments, microfluidic tools are currently experiment (c). being developed to select and sort single objects based on a specific FIGURE 2: Two-dimensional elemental map of the liquid- structural or functional criterion, before synchrotron analysis. liquid interface generated in a microfluidic mixer involving and FeCl3 solution (top) and a KOH solution (bottom) (a). X-ray absorption spectra recorded at positions A, B and C on panel (a), showing the evolution of the iron ion oxidation state along the interface (c). 85