Fig. 16

FTIR-2D imaging of unsoiled Azo Yellow Golden MSA mock-up, showing an area cleaned with Nanorestore Gel^® Peggy 6 loaded with tri-ammonium citrate at 1% w/w (a, b) followed by a clearance step using a Nanorestore Gel^® Peggy 6 hydrogel (exposure time for both steps: 2 min) and an unsoiled control (c, d). Possible TAC residues were assessed by mapping the IR symmetric oscillations of the carboxylate ion at 1550 cm⁻¹ (marked with an asterisk). All maps are 700 × 700 µm². The corresponding FTIR spectra are shown in the right panel. Each spectrum relates to a single pixel (5 × 5 µm²) of the corresponding 2D imaging map