Gaschromatographische retentionsdaten und struktur chemischer verbindungen

Prediction of retention indexes. I. Structure-retention index relationship on apolar columns

A simple method is reported for predicting the retention index (RI) of a chemical compound from the number of carbon and carbon equivalent atoms in the molecule, the RI increment for atom addition and the group retention factors (GRFs) for substituents and functional groups. Atoms other than carbon such as oxygen, nitrogen, sulfur, chlorine, bromine and iodine are assigned carbon atom equivalency of approximately 1, 1, 2, 2, 3 and 4, respectively and are counted for their contribution towards RI prediction. The GRFs of substituents and functional groups are derived from the RIs of reference compounds and series of homologues. Ring structures, ring fusion, ring connection, iso- and neo-carbons, chain branching and unsaturation are also assigned GRFs. The predicted RIs of a number of alicyclic, aliphatic and aromatic hydrocarbons, primary, secondary and tertiary alcohols, phenols, aliphatic amines, aromatic amines, heterocyclics, carboxylic acids, acid esters, aldehydes, ketones, and halogenated compounds, are found to be within +/- 3% of the observed values. The structure-retention index relationship thus developed is extremely useful in the tentative identification of radioactive side products formed in tritium labeling by radiation-induced methods.

Structure assignment by retention index in gas-liquid radiochromatography of substituted cyclohexenes

Substituents and functional groups cause increase in retention indexes of six-membered ring compounds on apolar and polar columns. These retention index increments (delta I) are characteristic and structure-dependent showing a structure-retention index relationship. The delta I values obtained for methyl and halogen atom substitution, cyclohexenes, and cyclohexanes are useful for predictive purpose in tritium labeling studies for tentative structure assignment of radioactive intermediates not amenable to analysis by conventional techniques.