JOURNAL OF MASS SPECTROMETRY J. Mass Spectrom. 2006; 41: 527–542 Published online 15 March 2006 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/jms.1011 Laser ablation and secondary ion mass spectrometry of inorganic transition-metal compounds. Part I: comparison between static ToF-SIMS and LA-FTICRMS Fr ´ ed ´ eric Aubriet, 1,2* Claude Poleunis, 1 Jean-Fran ¸ cois Muller 2 and Patrick Bertrand 1 1 Unit ´ e de Physico-Chimie et de Physique des Mat ´ eriaux, Universit ´ e catholique de Louvain, Croix du Sud 1, B-1348 Louvain-la-Neuve, Belgium 2 Laboratoire de Spectrom ´ etrie de Masse et de Chimie Laser, Universit ´ e de Paul Verlaine-Metz 1, Boulevard Arago, F-57078 Metz Technopole 2000 Cedex 03, France Received 17 January 2006; Accepted 19 January 2006 Most of the first-row transition-metal oxides, M A O B (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn) were examined by static secondary ion mass spectrometry (s-SIMS) and laser ablation/ionization Fourier transform ion cyclotron resonance mass spectrometry (LA-FTICRMS). Positive and negative ions show strong correlation between the studied oxide and the detected cluster ions. Specific M x O y +/- species were systematically observed with both MS techniques for each investigated M A O B transition-metal oxide. Moreover, the ion composition and ion distribution are greatly dependent on the ionization technique. Laser ablation (LA)/ionization leads to larger cluster ions (ionic species with nearly hundred atoms were in particular detected for Sc 2 O 3 and Y 2 O 3 oxides), whereas hydrogenated, dihydrogenated, and sometimes trihydrogenated species were observed in s-SIMS. However, the ion distribution for a given M x O y +/- ion series (i.e. ions including the same number of metal atoms M) generally presented important similarities in both techniques. Finally, it was demonstrated that the chemical state of metal atoms in the observed ionic species is closely dependent on the metal electronic valence shell. High valence states (+III, +IV, +V, and +VI) are favored for metals with a less-than-half full valence shell configuration, whereas for other first-row transition metals (manganese, iron, cobalt, nickel, copper and zinc) lower metal valence states (0, +I or, +II) are involved. Copyright  2006 John Wiley & Sons, Ltd. KEYWORDS: transition-metal oxides; UV laser ablation; Ga C ion sputtering; cluster ions; metal– oxygen species INTRODUCTION Transition-metal oxides are the subject of considerable interest because of their important role in a variety of processes including catalysis, corrosion, combustion, and biological systems. One of the most powerful methods to investigate such systems is mass spectrometry (MS). To generate oxygenated metal cluster ions from solid samples, many techniques such as 252 Cf plasma desorption, 1,2 ion bombardment in static mode 3–14 or laser ablation (LA) 15 – 28 are available. Owing to their versatility, laser ablation mass spectrometry (LA- MS) and static secondary mass spectrometry (s-SIMS) are the most employed techniques in the inorganic MS field. The use of plasma desorption mass spectrometry (PDMS) is more recent, especially in various fields of material science. L Correspondence to: Fr´ ed´ eric Aubriet, Laboratoire de Spectrom´ etrie de Masse et de Chimie Laser, Universit´ e de Paul Verlaine-Metz 1, Boulevard Arago, F-57078 Metz Technopole 2000 Cedex 03, France. E-mail: aubriet@univ-metz.fr Contract/grant sponsor: Belgium’s Federal State; Contract/grant number: PAI-IUAP P4/10. Inorganic MS may also be used for mineral compound speci- ation or differentiation in the solid state, 10 – 14,18 – 32 followup of corrosion processes, 33 syntheses of thin films, 34 – 37 characteri- zation of catalysts or modifications of catalyst surfaces. 7–11 As an example, LA-MS was used to quantify hydroxyl groups and to measure the specific surface area of different silica gels. 38,39 LA-MS and s-SIMS have potentially the same capabilities for the differentiation of inorganic compounds. In two recent studies of chromium compounds, it was shown that comparable criteria may be used to distinguish between trivalent and hexavalent chromium oxides by LA-MS 40 or s-SIMS. 41 Note, however, that their application range is quite different. The depth penetration of photon and primary ions, and hence the volume interrogated, is very different for s-SIMS, which is known as a very surface sensitive technique, and LA-MS, which involves a much larger analyzed volume. The goal of this study is to determine whether differen- tiation of metal oxides can be deduced, and whether better information can be generated by SIMS and LA. In the phe- nomenological analytical part of this study, our attention Copyright  2006 John Wiley & Sons, Ltd.