Figure 1
The thin-layer chromatogram obtained for toner-on-paper samples taken from the Q1, Q2, and eight reference documents (photographed under daylight). The TLC plate was developed sequentially in the following two solvent systems: 1) ethyl acetate / isopropanol / water / acetic acid = 30:15:10:1, and 2) ethyl acetate / ethanol / water = 70:35:30. For the TLC analysis, two 1-mm toner-on-paper samples were taken from each of the Q1, Q2, and eight K documents, and another three 1-mm toner-on-paper samples were taken from the Q1 document (sample “Q1-b”).
Figure 2
The solubility tests conducted for toner-on-paper samples taken from the Q1 and Q2 documents: the samples were extracted in chloroform, and the color intensities of the extracts were visually evaluated 10 seconds and 10 minutes after the beginning of the extraction process.