SEM-EDX Analysis of Insulator Specimens by Diluted Ionic Liquid —Application to Volcanic Particles—

Ethanol diluted (1 wt%) ionic liquid 1-ethyl-3-methylimidazolium acetate is used in order to avoid the charge-up of insulator specimen for scanning electron microscope (SEM) analysis. SEM-EDX analysis is additionally performed for the specimen treated by the ethanol diluted ionic liquid. As an example of the insulator specimen, we analyze volcanic ash particles, and succeed to discriminate the elemental composition difference of a specimen surface within 10 μm²micro area. Though a clear secondary electron image of the volcanic ash particle of which diameter is less than 10 μm can be obtained without electric conductive treatment, particles of diameter larger than 20 μm are needed to be treated by the diluted ionic liquid to avoid the charge-up effects.