Large Cluster Ions Desorbed from Organic Salts under Particle Bombardment

The sizes and Intensities of cluster Ions formed by fast atom bombardment from a series of organic salts In nearly saturated solutions have been evaluated. Clusters Involving as many as 29 anions and 30 cations have been recorded for cesium perfluorohexanesulfonate. The average mass of this n = 29 cluster Is 15 561.1. Abundances of the cluster Ions are found to vary as a function of salt concentration In the liquid matrix and the number of Ion pairs In the clusters. The abundance of the organic salt cluster [formula-omitted] at m/z 10 240.4 was found to be 8 times greater than the abu-dance of the Cs₄₀I₃₉ cluster at m/z 10265.5. The relatively high abundances of the sulfonate clusters permit them to be analyzed by using unit resolution In the high-mass range (for example at m/z 8110.5) and suggest that they may be useful as mass-marking reference compounds.