Emission of noble and transition metal adducts in organic secondary ion mass spectrometry

Abstract

Desorption of organic secondary ions containing one or more noble or transition metal atoms (Ag, Au, Cu, Ni, Co) has been observed for various organic compounds (pyrimidine derivatives, 1,10-phenanthroline) using metal supports or by adding metal salts to the target. The secondary ion mass spectra generally exhibit (M + C) +, (C = metal atom), as the major metal adduct. With transition metals, however, this adduct is partially or even totally substituted for (M + CH) +. Cluster ions (2M + C) + not observed for pyrimidine derivatives are also observed with the chelating agent 1,10-phenanthroline. In addition to these processes, further incorporation of metal atoms (metal/hydrogen substitution) occurs for compounds containing acidic hydrogen atoms; this phenomenon is much less important however than with alkali metals. Finally, cationization processes involving noble or transition metals dramatically affect the fragmentation patterns observed in the secondary ion mass spectra. In particular, much higher yields of metal-containing fragment ions are observed with transition metals than with noble or alkali metals.