The analytical use of mass spectra from static secondary ion mass spectrometry for the molecular identification of inorganic analytes in real life surface layers and microobjects requires an empirical insight in the signals to be expected from a given compound. A comprehensive database comprising over 50 salts has been assembled to complement prior data on oxides. The present study allows the systematic trends in the relationship between the detected signals and molecular composition of the analyte to be delineated. The mass spectra provide diagnostic information by means of atomic ions, structural fragments, molecular ions, and adduct ions of the analyte neutrals. The prediction of mass spectra from a given analyte must account for the charge state of the ions in the salt, the formation of oxide-type neutrals from oxy salts, and the occurrence of oxidation-reduction processes.

This paper presents a systematic study of pure inorganic binary salts using a time-of-¯ight (TOF) static secondary ion mass spectroscopy (S-SIMS) instrument. The objective was to evaluate the methodÕs capability to achieve molecular speciation of binary salts. The results show the feasibility of direct speciation in a deductive manner without the need for reference spectra. Also ratioing intensities of speci®c high-m/z cluster ions can dierentiate compounds with the same elements in dierent oxidation states. Ó

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A first attempt to measure the molecular compositions of pigments in paintings using static SIMS was made. An investigation of pellets of pure pigments such as auripigment and verdigris allowed the detection of numerous high m/z ions useful for molecular identification. Analysis of pigments in embedded paint fragments, on the other hand, only yielded elemental information because of charge build-up and contamination problems. Optimization of the form in which the sample is presented to the analysis method is obviously the price to pay for the ultimate sensitivity and information depth of S-SIMS.