Massive cluster impact

Deposition of the analyte on nitrocellulose films instead of metal foils allows the removal of alkali ion contaminations by washing of the sample layer which results in better PD spectra. [163] Further improvements can be achieved by adsorption of the analyte molecules on top of an organic low-molecular weight matrix layer. [164,165] 

Obviously, Cf-PD creates ions in a pulsed manner - one burst of ions per fission event - analogous to laser desorption, a fact that restricted the adaptation of Cf-PD to time-of-flight (TOF) analyzers (Chap. 4.2). The second fission fragment is not useless, however, because it serves to trigger the time measurement of 

Example The Cf-PD mass spectrum of bovine insulin exhibits the [M+H] quasimolecular ion as well as the doubly charged [M+2H] and triply charged [M+3H] ion (Fig. 9.20). [156] Fragment ions corresponding to the A and B chain as well as some a-type peptide fragments ions are observed in addition. 

---

Mahoney, J.F. Perel, J. Ruatta, S.A. Martino, P.A. Husain, S. Lee, T.D. Massive Cluster Impact Mass Spectrometry a New Desorption Method for the Analysis of Large Biomolecules. Rapid Commun. Mass Spectrom. 1991, 5, 441-445. 

Massive cluster impact MQ generation of secondary ions by bombardment with massive clusters of up to 10 u I25] ... 

Mahoney, J.F. Perd, J. Lee, T.D. Martino, P.A. Williams, P. Shock Wave Model for Sputtering Biomolecules Using Massive Cluster Impact. J. Am. Soc. Mass Spectrom. 1992, 5,311-317. 

---