High Resolution ATR μ-FTIR to map the diffusion of conservation treatments applied to painted plasters

Here we demonstrate the extension of applicability of high resolution Attenuated Total Reflection Fourier transform infrared μ-mapping (ATR μ-FTIR) to the investigation of the diffusion of a conservation treatment, ammonium oxalate, within painted plasters. The method demonstrates its potentiality in situations where high lateral resolution is required and the compounds are not easily detectable with conventional analytical techniques. It was applied successfully to explore the interaction between ammonium oxalate solutions and the carbonatic matrix at the microscale. The reaction of the carbonatic aggregate particles was assessed as well as the influence of the treatment parameters on the penetration depth. High resolution ATR μ-FTIR represents a new spectroscopy imaging modality expanding the portfolio of chemically specific analytical tools.