Commercially Available Hand Creams - Sample Preparation for Cryo-SEM

Application Note for Leica EM HPM100 - Materials Research

November 18, 2016

Hand creams having different water contents were applied into the 100 μm cavities of two 3 mm type A sample carriers which were then closed cream sides inwards. The sample assembly was high pressure frozen with a Leica EM HPM100 and moved to a cooled Leica EM VCT100 loading station. The closed carriers were mounted on a universal sample carrier, withdrawn into an EM VCT100 shuttle then transferred into a Leica EM BAF060.

Samples were fractured by pushing the top carrier off with the fracturing knife at -140°C, then they were high angle rotary shadowed with platinum/carbon. The samples were again withdrawn into the EM VCT100 shuttle and then moved to the cryo-SEM. They were imaged with a Hitachi S4700 FE-SEM with the EM VCT100 CryoStage at –125°C.

Results
High pressure freezing followed by freeze fracture and cryo-SEM are well-suited for determining the structure of water-containing industrial materials. Multiple samples can be processed and examined within a short time with an SEM equipped with a Leica EM VCT100 cryo-stage.

Fig.1: Hand cream with high water content shows mostly large emulsified pockets of aqueous material interspersed between few lipid sheets.
Fig.2: Hand cream with low water content shows mostly lipid sheets with very small pockets of emulsified aqueous content.

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