## 3 Results
### Organic Pigment Analysis
#### 3.2.2 Pyrolysis products detected in gilding samples \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline
**Pyrolysis Products Identified** & **No.** &
\begin{tabular}{c} **Retention** \\ **Time** \\ \end{tabular} & **\#1** & **\#2** & **\#3** & **\#4** & **\#5** & **\#6** & **\#7** & **\#8** & **\#9** & **\#10** \\ \hline Glycine & 1 & 5.02 & + & + & + & + & + & + & & + & + & + \\
2-[2,N,N-Trimethyl-2-aminoethyl]benzofuran & 2 & 6.28 & + & + & + & + & + & + & & & \\
1,3,5-Triazine & 3 & 9.50 & + & + & + & + & + & & & & & \\ Butanediotic acid & 4 & 11.03 & + & + & + & + & + & & & + & + & + \\ Benzoic acid & 5 & 13.11 & + & + & + & + & & + & + & + & + \\ Oxalic acid & 6 & 13.54 & & + & + & + & & & & + & & \\ Methyl-1-methylpyrrole-2-carboxylate & 7 & 14.09 & + & + & + & + & + & & & & + & \\ Octanoic acid & 8 & 14.16 & & & + & + & + & + & & + & + & + \\ Sarcosine & 9 & 15.50 & + & & + & + & + & + & & + & & + \\ Pyrrolidine & 10 & 15.99 & & & & & & & & & & + \\ Pentanedoic acid & 11 & 16.25 & + & & & & & & & & & \\ DL-Alanine & 12 & 17.06 & & & + & + & & & & & & \\
3,5-Dimethylpyrimidine-2,4(IH,3H)-dione & 13 & 17.37 & & + & & & & & & & & \\ Nonanoic acid & 14 & 17.67 & + & + & & & & & + & + & + & + \\ Imidazole-c-carboxylic acid & 15 & 17.76 & + & & & & & & & & & \\ L-Aspartic acid & 16 & 18.00 & + & & + & + & + & & & & & \\ Hexanedoic acid & 17 & 18.43 & + & & & & & + & + & & + & + \\ Methyl-8-methyl-nonanoate & 18 & 21.07 & & & & & & & + & + & + & + \\ Prido[2,3-d]pyrimidine-2,4(IH,3H)-dione & 19 & 21.75 & + & + & & & & & & & \\ Heptadecinoid acid & 20 & 21.81 & & + & + & & & & & & \\ Pyrrolizin-1,7-dione-6-carboxylic acid & 21 & 22.15 & + & & + & & & & & & \\ Biphenyl & 22 & 22.79 & & & & & & & & & & \\ L-Proline & 23 & 22.90 & & & & + & & & & & & \\ Phenol & 24 & 24.75 & + & + & & & & + & + & + & + & + \\ Octanedoic acid & 25 & 25.05 & & + & + & + & + & + & + & + & + \\ Dimethyl phthalate & 26 & 25.25 & + & + & + & + & + & + & + & + & + & + \\
1,4-Benzenedicarboxylic acid & 27 & 26.60 & + & + & + & + & + & + & + & + & + & + \\
2,4-di-tert-butylphenol & 28 & 26.95 & + & + & & & & & + & + & + & + \\ Dodecanoic acid & 29 & 27.35 & + & + & + & & & & + & + & + & + \\ Nonanedio acid & 30 & 28.05 & + & + & + & + & + & + & + & + & + \\ Methyl tetradecaanoate & 31 & 32.97 & + & + & + & + & + & + & + & + & + & + \\ Undecadenoidic acid & 32 & 33.67 & & & + & & & & & & & \\
3,5-di-tert-Butyl-4-hydroxyphenylpropionic acid & 33 & 33.99 & + & & & & & & & & \\
1-Hexadecanol- & 34 & 34.80 & & & & & & & & & & \\ Pentadecanoic acid & 35 & 35.63 & & + & & + & & + & + & + & + \\ Hexadecanientrile & 36 & 37.50 & & & & & & & & + & + & + \\ Pyrrolizin-1,7-dione-6-carboxylic acid & 37 & 37.53 & & + & & & & & + & + & + & \\ Hexadecanoic acid & 38 & 38.15 & + & + & + & + & + & + & + & + & + \\
9-Octadecenientrile & 39 & 41.85 & + & + & & & & & + & + & + & + \\
13-Octadecen acid & 40 & 42.25 & + & + & & & & & + & + & + & + & + \\ Methyl stearate & 41 & 42.85 & + & + & + & + & + & + & + & + & + & + \\ NN’-Pentamethylelebis[-3-aminopropyl] & 42 & 43.44 & & + & + & & & & & & & \\ thiosulfritic acid & & & & & & & & & & & & \\ Deoxyperpain & 43 & 43.95 & + & + & & & + & + & + & & + & \\ Nonadecanamide & 44 & 44.20 & & & & & & & & & & \\ Shellolic acid & 45 & 45.40 & & & & & & & & & & \\ Phorbol & 46 & 46.35 & & & + & & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Pyrolysis products detected in gilding samples. are the original components of drying oils, while octanoic acid (C\({}_{8.0}\), No. 6), octanediolic acid (2C\({}_{8}\), No. 8), nonanediolic acid (2C\({}_{9}\), No. 30), and decandioic acid (2C\({}_{12}\), No. 29) are the typical aging products of drying oils [17]. P/S (palmitic acid/ stearic acid, C\({}_{16}\)/C\({}_{18}\)) is always considered to judge the type of drying oil [18]. The P/S value is a classical reference to determine the oil type, with values from 1.0-1.5 indicating the type as linseed oil, tung oil, and egg yolk [17].