A few micro liters of 10 −2 wt.% ionic liquid diluted by ethanol or acetone dropped onto insulating samples made it possible to observe scanning electron microscope (SEM) image at 5000 magnification, which is as clear as Pt-Pd sputtering. SEM-EDX analysis of sulfur is possible when using sulfur-free ionic liquid diluted down to 10 −2 wt.%. Quantitative analysis using the ZAF method is also possible for insulating samples.