Rapid Screening of Calcium Carbonate Precipitation in the Presence of Amino Acids: Kinetics, Structure, and Composition
journal contributionposted on 26.07.2016, 00:00 by David C. Green, Johannes Ihli, Yi-Yeoun Kim, Samantha Y. Chong, Phillip A. Lee, Christopher J. Empson, Fiona C. Meldrum
Soluble additives are widely used to control crystallization, leading to a definition of properties including size, morphology, polymorph, and composition. However, because of the number of potential variables in these experiments, it is typically extremely difficult to identify reaction conditionsas defined by solution compositions, temperatures, and combinations of additivesthat give the desired product. This article introduces a high-throughput methodology which addresses this challenge and enables the streamlined preparation and characterization of crystalline materials. Using calcium carbonate precipitated in the presence of selected amino acids as a model system, we use well plates as microvolume crystallizers, and an accurate liquid-handling pipetting workstation for sample preparation. Following changes in the solution turbidity using a plate reader delivers information about the reaction kinetics, while semiautomated scanning electron microscopy, powder X-ray diffraction, and Raman microscopy provide structural information about the library of crystalline products. Of particular interest for the CaCO3 system is the development of fluorescence-based protocols which rapidly evaluate the amounts of the additives occluded within the crystals. Together, these methods provide a strategy for efficiently screening a broad reaction space, where this can both accelerate the ability to generate crystalline materials with target properties and develop our understanding of additive-directed crystallization.
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Composition Soluble additivespowder X-ray diffractionRaman microscopysolution turbidityRapid ScreeningCalcium Carbonate PrecipitationmaterialCaCO 3 systemsample preparationcontrol crystallizationadditive-directed crystallizationplate readerAmino Acidscalcium carbonatereaction spacemicrovolume crystallizersliquid-handling pipetting workstationtarget propertiesinformationsolution compositionsreaction kineticssemiautomated scanning electron microscopymodel systemfluorescence-based protocolshigh-throughput methodology