Supplementary Material for the article "Ready-to-use, simple, and accurate empirical equations for the estimation of gas chromatographic retention indices for the DB-225MS stationary phase"

The models published in the literature for predicting the value of the gas chromatographic retention index based on the structure of a molecule are not frequently employed in practice due to their low accuracy, the necessity for the use of paid software to calculate molecular descriptors, and the very narrow applicability domain of many models. In recent years, models based on deep learning have emerged that can achieve acceptable prediction accuracy for a wide range of molecules. These models are now being used in practice as an additional criterion in GC-MS identification. The DB-225MS stationary phase (50%-cyanopropylphenyl-methylpolysiloxane) is widely used in practice, but usable models for estimating retention indices are not available for this stationary phase. This study presents such models for the first time. Spreadsheet contains 6 sheets. The contents of the sheets are shown below. The file contains datasets (with sources), molecular descriptor values and prediction equations ready for use.

S1. Training set: compound structures, experimental retention indices (DB-225MS), predicted retention indices, molecular descriptor values
S2. Test set: compound structures, experimental retention indices (DB-225MS), predicted retention indices, molecular descriptor values
S3. External test set (esters)
S4. External test set (phenols)
S5. Information about molecular descriptors
S6. Python code snippet for calculating molecular descriptors and predicting retention indices, equations for predicting retention indices.
Sources from which data are used:
Yan J, Liu X-B, Zhu W-W, et al. Retention Indices for Identification of Aroma Compounds by GC: Development and Application of a Retention Index Database. Chromatographia. 2015;78(1–2):89–108. doi: 10.1007/s10337-014-2801-y.
Ashes JR, Haken JK. Gas chromatography of homologous esters. Journal of Chromatography A. 1974;101(1):103–123. doi: 10.1016/S0021-9673(01)94737-5.
Grzybowski J, Lamparczyk H, Nasal A, et al. Relationship between the retention indices of phenols on polar and non-polar stationary phases. Journal of Chromatography A. 1980;196(2):217–223. doi: 10.1016/S0021-9673(00)80441-0.