Desorption/ionization on carbon mass spectrometry: study of amorphous-carbon property.

Abstract

In this study, an amorphous carbon was proposed as a new ionization substrate for laser desorption/ionization (LDI) and its efficiency for soft laser ionization without any matrix molecules was focused on the soft laser ionization effect of the amorphous carbon substrate was compared with that of a stainless substrate by LDI and matrix-assisted laser desorption/ionization (MALDI) using a 266-nm irradiation laser. The result of the amorphous carbon substrate was indicated to have a soft ionization effect similar to the result of MALDI. In addition, from the experimental result achieved by soft laser ionization using not only 266-nm-wavelength but also 355-nm-wave length irradiation lasers, the amorphous carbon substrate had a high degree of generality for selecting a sample similarly to soft ionization. The same experimental condition was carried out for other amorphous carbon substrates with different surface roughnesses in order to clarify the ionization mechanism on the amorphous carbon substrates. From the results, it was suggested that factors besides the difference in surface roughness exist for laser ionization efficiency.