Possibility of scanning electron microscope observation and energy dispersive X-ray analysis in microscale region of insulating samples using diluted ionic liquid.

: The possibility of scanning electron microscope (SEM) observation and energy dispersive X-ray (EDX) spectrometry analysis in microscale regions of insulating samples using diluted ionic liquid was investigated. It is possible to obtain clear secondary electron images of insulating samples such as a rock and mineral at 5,000 times magnification by dropping 10 μL of 1 wt% of 1-ethyl-3-methylimidazolium acetate (EMI-CH₃COO) diluted with ethanol onto the samples. We also obtained EDX spectra of the samples in microscale regions (~5 μm²) without overlapping EDX spectra of other minerals with different composition. It might be possible to perform quantitative analysis of the samples if a method that does not need standard samples is applied or an X-ray detector sensitive for light elements was attached. The method of dropping 1 wt% EMI-CH₃COO diluted with ethanol onto insulating samples is useful for SEM observation, EDX analysis in microscale regions, and the preservation of scarce rock and mineral samples because ionic liquid can be easily removed with acetone.