Enhancement of the static SIMS secondary ion yields of lipid moieties by ultrathin gold coating of aged oil paint surfaces

• Published in: Surface and interface analysis Vol. 36; no. 13; pp. 1620 - 1628
• Main Authors: Keune, K., Boon, J. J.
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 2004; Wiley
• Subjects: Applied sciences; Atomic, molecular, and ion beam impact and interactions with surfaces; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron and ion emission by liquids and solids; impact phenomena; Exact sciences and technology; fatty diacids; gold coating; Impact phenomena (including electron spectra and sputtering); Metals. Metallurgy; monocarboxylic acids; oil paint; Physics; static SIMS; Ultrathin films; Gold; fatty diacids; Surface coating; Lipids; Optimization; Octadecanoic acid; static SIMS; Yields; monocarboxylic acids; Pigments; SIMS; gold coating; Oil paint
• ISSN: 0142-2421; 1096-9918
• DOI: 10.1002/sia.1996

Static secondary ion mass spectrometry (SIMS) is a powerful technique for identification and localization of pigments and binding media present in traditional paintings. Coating the surface of a cross‐section with a 20 Å thick gold layer improves the yields of secondary ions from the fatty acids and diacids. A chalk tablet containing 1% stearic acid, which was partially covered during gold deposition, is used as a test system to investigate the increase of the organic secondary ion yields upon gold deposition in SIMS imaging. A comparative study of a native and gold‐coated aged surface of a lead white‐containing linseed oil paint demonstrates the enhancement of the organic ion yields on a sample relevant for painting studies. The yields of oil paint‐derived negative ions increase by a factor of 3 whereas the yields of positive ions increase by a factor of 2–4. The different types of charged functional groups determine the degree of improvement in yield. Gold coating improves the ionization process of the fatty acids and does not influence their fragmentation. The dissociation of the lead white by the primary ion beam is reduced due to the gold coating. Copyright © 2004 John Wiley & Sons, Ltd.