F. Moreover, F shows intense peaks in the re- gion of 3- and 4-ring aromatics, which are par- ticularly due to phenanthrene and anthracene (C14H10) as well as pyrene and fluoranthene (C16H10). Intense oxygen heteroaromatics such as dibenzofuran (C12H8O) and xanthene (C13H9O) also occur in the same range. Nitro- gen-containing intense compounds are 9H-car- bazole-9-methanol (C13H11NO) and acridine (C13H9N). Dibenzothiophene (C12H8S) repre- sents the most intense sulphur compound. Fig. 1. GC x GC-chromatograms after peak picking and classification of base peaks into the four classes: CH (grey), N (green), O (red) and S (yellow). Chromatograms are shifted 1.5 s in the second dimension to adjust wrap-around. Peak areas are represented by bubble sizes. Intense areas from 9000 seconds are due to col- umn bleeding. In comparison, the compounds in P are clearly shifted towards higher molecular weights. The 5- and 6-ring aromatics predomi- nate, such as benzo[k]fluoranthene (C20H12), indeno[1.2.3-cd]pyrene (C22H12) and in- deno[1.2.3-fg]naphthacene (C24H14). The amount of heteroatomic compounds is very low in this fraction. However, some intense nitro- gen compounds can be detected, mainly at- tributable to dibenzocarbazoles and napthocarbazoles (C20H13N). Fig. 2. 3D-Isoabundance plots of double bond equivalents (DBE) vs. carbon number (#C) for the compound class of hydrocarbons detected by DIP-HRMS. Bubble sizes represent normal- ized peak areas. Due to limited temperature range of GC x GC in combination with a large semi- and non-volatile fraction of CTP-binders, addi- tional DIP-HRMS experiments were per- formed. Because of the reduced pressure inside the ion source, the boiling points of the com- pounds are shifted to lower temperatures9. This allows the investigation of the semi-volatile fraction. The gradual increase in temperature results in a slight separation of the sample based on different boiling points.