Semi-quantitative characterisation of binary salt mixtures with static secondary ion mass spectrometry (S-SIMS)

• Published in: International journal of mass spectrometry 2005-12, Vol.247 (1), p.28-36
• Main Authors: Van Ham, Rita, Van Vaeck, Luc, Adriaens, Annemie, Adams, Freddy, Hodges, Brittany, Appelhans, Anthony, Groenewold, Gary
• Format: Article
• Language: English
• Subjects: Binary salts; Mixtures; Polyatomic; Quantification; Sample preparation; Static-SIMS
• ISSN: 1387-3806; 1873-2798
• DOI: 10.1016/j.ijms.2005.07.010

The use of static secondary ion mass spectrometry for the semi-quantitative characterisation of major components by means of molecule specific ion signals has been investigated for binary salts. The calibration of the peak intensities as a function of the local concentration has been based on reference mixtures. The preparation of the mixtures has been proven to be a major bottleneck. Five different approaches have been tried out. Fast freezing with subsequent cryo-lyophylisation is the preferred method to obtain adequate molecular mixtures for the empirical calibration of relative peak intensities in S-SIMS as a function of the local concentration. The applicability has been verified in two different laboratories and three instrumental S-SIMS configurations. Monoatomic as well as polyatomic primary ions have been used. Specifically, comparative work involved the use of Ga + primary ions in a time-of-flight (TOF) S-SIMS and ReO 4 − polyatomic projectiles in an ion trap and a triple quadrupole instrument, used in the single mass selection mode. In all cases, the local content can be determined with an experimental uncertainty of 10–20% using the molecular (adduct) ion signal intensities in either the positive or negative ion detection mode.