Studying crystallisation processes using electron microscopy: The importance of sample preparation Ilett, Martha Afzali, Maryam Abdulkarim, Bilal Aslam, Zabeada Foster, Stephanie Burgos Ruiz, Miguel Kim, Yi-Yeoun Meldrum, Fiona C. Drummond-Brydson, Rik M. Crystallisation Electron microscopy Sample preparation We present a comparison of common electron microscopy sample preparation methods for studying crystallisation processes from solution using both scanning and transmission electron microscopy (SEM and TEM). We focus on two widely studied inorganic systems: calcium sulphate, gypsum (CaSO4·2H2O) and calcium carbonate (CaCO3). We find significant differences in crystallisation kinetics and polymorph selection between the different sample preparation methods, which indicate that drying and chemical quenching can induce severe artefacts that are capable of masking the true native state of the crystallising solution. Overall, these results highlight the importance of cryogenic (cryo)-quenching crystallising solutions and the use of full cryo-TEM as the most reliable method for studying the early stages of crystallisation. 2024-05-16T11:48:57Z 2024-05-16T11:48:57Z 2024-04-09 journal article Ilett, M., Afzali, M., Abdulkarim, B., Aslam, Z., Foster, S., Burgos-Ruiz, M., Kim, Y.-Y., Meldrum, F., & Drummond-Brydson, R. M. (2024). Studying crystallisation processes using electron microscopy: The importance of sample preparation. Journal of Microscopy, 1–14. [https://doi.org/10.1111/jmi.13300] https://hdl.handle.net/10481/91884 10.1111/jmi.13300 eng http://creativecommons.org/licenses/by/4.0/ open access Atribución 4.0 Internacional Wiley