## 3 Results and Discussion
### Characterizations of Oil Painting After Varnish Removal
#### 3.3.2 Gas Chromatography-Mass Spectrometry (GC/MS)  
The GC/MS made it possible to quantify the fatty acids contained in each sample, expressed in Table 3 as \(\upmu\)g/100 \(\upmu\)g. The leaching action on the pictorial surface of each treatment can therefore be deduced. As a blank, samples treated only with D5 were analyzed to evaluate the removal effect given by the siloxane alone (\"D5\" in Table 3, the reported values were obtained by the average of three measurements). Furthermore, checks were carried out on the swabs before use to verify that they do not release fatty acids during varnish removal. Before being used, these swabs were immersed in MeOH for 10 min, sonicated for 20 min, washed in EtOH, and finally placed in a desiccator. On an average of 6 swabs analyzed with GC/MS, leaching of 0.03 \(\upmu\)g/100 \(\upmu\)g was detected. Data are not reported in Table 3. The results from the GC/MS analysis are listed in Tables 3 and 4, expressed as \(\upmu\)g of fatty acid over 100 \(\upmu\)g of treated samples. In Tables 3 and 4, the \"NT\" sample refers to the untreated sample. Average values of the analyte for three starting samples are considered and analyzed to obtain an estimate of the starting fatty acids. Figure 5: Cross-section of not-treated sample: elementary maps of zinc, barium, sulfur, titanium, and calcium. Scale bar: 150 \(\upmu\)m.  
BAl applied pure through a cotton swab quickly removed the varnish. However, as can be seen from Table 3 (sample 0), it caused strong leaching, removing significant amounts of fatty acids. C9 di, C16, and C18 appear to be the most affected. Saturation with D5 (sample 0D) reduced the interaction, which however remained at a rather high level. When BAI was the dispersed phase of a surfactant-free emulsion with the pH 7 buffered aqueous phase gelled with Vanzan NF-CTM, the 5% concentration was sufficient to produce the expected removal of the varnish. Little ionizing action on the varnish terpenoid molecules can be expected by the aqueous medium at this pH; therefore, varnish removal can be attributed to the solvent effect of the alcohol, perhaps with an emulsifying/dispersing contribution from the gelling polymer on the swollen resinous material. Figure 6: FT-IR spectra on 8 and 8D samples after varnish removal. \begin{table}
\begin{tabular}{c c c c c} \hline \multicolumn{2}{c}{**Analyte**} & \multicolumn{4}{c}{**Samples**} \\ \hline  & **NT** & **0** & **0D** & **D5** \\ \hline  & & \multicolumn{4}{c}{(\(\upg\)/100 \(\upg\))} \\ \hline C9 di & 0.37 (4) & 0.25 (3) & 0.19 (9) & 0.27 (2) \\ \hline C14 & 0.04 (1) & 0.02 (1) & 0.02 (1) & 0.04 (1) \\ \hline C15 & 0.01 (0.5) & 0.01 (0.5) & 0.01 (0.5) & 0.02 (1) \\ \hline C16 & 0.47 (5) & 0.26 (6) & 0.40 (3) & 0.37 (3) \\ \hline C18:1 & 0.07 (1) & 0.03 (1) & 0.03 (0.6) & 0.05 (1) \\ \hline C18 & 0.44 (4) & 0.22 (8) & 0.28 (3) & 0.39 (3) \\ \hline C20 & 0.01 (0.5) & 0.01 (0.5) & 0.03 (1) & 0.03 (1) \\ \hline C22 & 0.02 (1) & 0.01 (0.5) & 0.02 (1) & 0.04 (1) \\ \hline TOT & 1.43 & 0.81 & 0.98 & 1.21 \\ \hline \% present & 100 & 54 & 67 & 84 \\ \hline \% removed & 0 & 46 & 33 & 16 \\ \hline \end{tabular}
\end{table} 
Table 3: Varnish removal with BAI (samples 0 and 0D), compared with siloxane (D5) and untreated sample (NT). Abbreviations used are as follows: C9 di, azelaic acid; C14, myristic acid; C15, pentadeconic acid; C16, palmitic acid; C18:1, oleic acid; C18, stearic acid; C20, arachidonic acid; C22, behenic acid. Standard deviation reported in parenthesis. This was the crucial fact to verify: if the dispersed phase was a solvent completely immiscible with the aqueous dispersing phase, then it would be emulsified, that is, 'hidden' in the chains of the gelling polymer as in a true micellar structure. But, as we have described, the alcohol has a non-negligible miscibility in water, around 4%.