Properties of [C.sub.84] and [C.sub.24][H.sub.12] molecular ion sources for routine TOF-SIMS analysis

[C.sub.84.sup.+] and coronene ([C.sub.24][H.sub.12.sup.+]) have been studied as primary ions for use in secondary ion mass spectrometry. A representative range of samples has been used to compare the effectiveness of each primary ion with the existing [C.sub.60.sup.+], [Au.sup.+], and [Au.sub.3.sup.+] primary ions. It was found that [C.sub.84] is the most effective primary ion providing higher secondary ion yields and a high molecular to fragment ion ratio. Coronene had a performance similar to [C.sub.60]. Coronene and [C.sub.60] primary ions were also used to extend a previous study of matrix suppression/enhancement effects. The [C.sub.60] was found to ameliorate this effect, possibly due to the increase in protonation in polyatomic sputtering, and coronene was found to further reduce suppression showing evidence of a chemical effect.