Global Chromatography Node. In our previous work, we used a global graph node connected to all other nodes in the molecular graph with special edge types to encode global properties such as spectral phase (i.e., gas phase, nujol mull, CCl4, etc). These global features were expressed as one-hot encodings (analogous to atomic number) and were found to generate embeddings that reflected the global state in the context of the molecular structure itself. For IR spectral predictions, this structural context was useful for predictions of bathochromic shifts, where the solvent phase can cause varying shifts in specific IR frequencies. This contextualization of predictions inspires confidence that the use of a global graph node improves model understanding of emergent chemistry. For retention time prediction across different chromatographic setups, we believe that molecular context is of the upmost importance. Not all functional groups will interact identically with the stationary or mobile phase, and these interactions and they impact retention times may change, or scale differently based on chromatographic conditions. Mobile phase pH provides an illustrative example in this regard. For molecules with ionizable functional groups, a difference of 2 pH units in the mobile phase may represent (de)protonation of those functional groups, creating a dramatic difference in retention time driven primarily by ionic or hydrophobic interactions with a C18 column. For molecules without ionizable functional groups, the shift in pH will likely not be as meaningful. By describing these parameters by a global chromatography node, we allow Graphormer's attention mechanisms to derive relationships between the nodes in the graph (including the global node) that allows models to derive relationships between the molecular structure and these global features. If we simply use the traditional approach and append these features to the latent dense "fingerprint" representation (see Figure ), the decoding MLP loses ability to consider these properties in the context of the molecular structure because the tensor containing the chromatographic information loses its description of graph structure.