ToF-SIMS Parallel Imaging MS/MS of Lead Soaps in Embedded Paint Cross Sections.

Area of Science:

• Analytical Chemistry
• Materials Science
• Art Conservation Science

Background:

• Metal soaps, particularly lead soaps, are common degradation products in oil paintings.
• Understanding their distribution is crucial for the conservation of cultural heritage.
• Previous methods lacked the specificity and spatial resolution for unambiguous identification.

Purpose of the Study:

• To develop and demonstrate a method for the unambiguous identification and localization of lead soaps in oil painting cross-sections.
• To utilize advanced mass spectrometry imaging for high-resolution chemical analysis of aged paint samples.

Main Methods:

• Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) with tandem mass spectrometry (MS/MS) imaging.
• Analysis of cross-sections from old oil painting samples.
• Characterization of specific fragmentation patterns of lead soaps.

Main Results:

• Successfully identified and localized lead soaps within oil painting cross-sections at high spatial resolution.
• Demonstrated that lead soap fragmentation is characterized by lead ion loss and fragmentation along hydrocarbon chains.
• Established a reliable method for detecting these degradation products.

Conclusions:

• ToF-SIMS tandem MS imaging is a powerful tool for unambiguous lead soap identification in cultural heritage objects.
• This technique provides new insights into the chemical processes of oil paint degradation.
• The method can be applied to study organic pigments and binders in historical artworks.