Chemometrics to chemical modeling: Structural coding in hydrocarbons and retention indices of gas chromatography

Abstract

Systematic studies were performed on an application of chemometrics to molecular modeling and the regularity of the retention index (RI ) of gas chromatography (GC). Molecular structures of hydrocarbons in straight-run gasoline were numerically coded. A set of structural parameters was accordingly obtained for the hydrocarbons and found correlate to their GC retention indices. A quantitative structure-retention relationship (QSRR) model (M1), with a correlation coefficient of R = 0.9901 and a standard deviation (SD) error of SD = 20.24, between the numeric structural codes and GC retention indices of 150 hydrocarbons was developed using multiple linear regression (MLR). If a “leave-one-out” cross-validation procedure was employed to construct a QSRR model for all samples, a second model (M2) with R = 0.9874 and SD = 22.87 was generated. The structural codes of hydrocarbons were tested with MLR for estimation and prediction of the GC RI by models M1 and M2, and the results obtained proved to be satisfactory.