DOI: 10.6084/m9.figshare.26119558.v2
title: A data set of retention indices and retention times for 200+ molecules and two stationary phases (gas chromatography)

description: Retention indices based on n-alkanes are a relative measure of the retention of chemical compounds in gas chromatography. Unlike retention times, retention indices are independent of most experimental conditions (flow rate, temperature, etc.) and depend mainly on the type of stationary phase and the structure of the compound. This is a small free data set made by us containing times and retention indices of 200+ organic molecules. The data were obtained under gas chromatography conditions.A set of 240 organic compounds of various chemical natures was used. Most of the compounds were purchased from commercial suppliers. All standard samples were tested by GC-MS (electron ionization) using the NIST 17 database. A standard mixture of C7-C40 n-alkanes was used (1000 μg/ml of each component in hexane, Sigma-Aldrich). Acetonitrile (UHPLC-Supergradient PAI-ACS, Panreac) was used to dissolve standard compounds. A sample of 1.5 mg of solid or 1 μL of liquid of each substance was dissolved in 1 mL of acetonitrile. Analyzes were carried out on a gas chromatograph-mass spectrometer Shimadzu GCMS-TQ8040 with a quadrupole mass analyzer. Up to 10 compounds (~1.5 mg/ml each) were mixed in one batch. When peak annotation was ambiguous, measurements of individual compounds were performed.The following chromatographic columns were used: ZB-5MS (60 m x 0.25 mm x 0.25 μm, Agilent) and SH-Stabilwax (30 m x 0.25 mm x 0.1 μm, Shimadzu). Length, inner diameter, and thickness of the layer are given.Measurements on the ZB-5MS column were performed under the following conditions: temperature of injector: 250 °C; temperature of ion source: and 200 °C; carrier gas: He; flow control mode: constant linear velocity; column flow rate: 1.47 ml/min; injection split ratio: 1:50; temperature programming: the temperature was kept at 30 °C during 5.5 min, then raised from 30 °C to 320 °C at 4 °C/min rate and then was kept constant during 10 min; the mass detector was used in electron ionization mode at 70 eV, scan rate: 1666 units/s, mass range: 44 - 500 m/z.Measurements on the SH-Stabilwax column were performed under the following conditions: temperature of injector: 250 °C; temperature of ion source: and 200 °C; carrier gas: He; flow control mode: constant linear velocity; column flow rate: 1.0 ml/min; injection split ratio: 1:50; temperature programming: the temperature was raised from 50 °C to 240 °C at 8 °C/min rate and then was kept constant during 30 min; the mass detector was used in electron ionization mode at 70 eV, scan rate: 2500 units/s, mass range: 45 - 500 m/z.The data set can be used in chemical analysis and as a benchmark for machine learning. The data set contains 240 entries for the non-polar stationary phase (ZB-5MS) and 202 for the polar stationary phase (SH-Stabilwax).Predictions of retention indices for a range of molecules made using seven machine learning models published in the literature are given in predictions.xlsxThis research was supported by the Ministry of Science and Higher Education of the Russian Federation (№ 124041900012-4).