Statistical Analysis of Gas Chromatography Retention Index Database

Gas chromatography/mass spectrometry (GC/MS) is widely used for compound identification in metabolomics. In order to increase the confidence of the compound identification, several retention index databases were developed. Theoretically, retention indices should be systemic-independent and especially be independent from column length, column diameter, and stationary film thickness. To investigate whether the RI database is consistent with these properties, we performed the statistical analysis between RI values and several experimental conditions using parametric and nonparametric methods based on the NIST RI database. Our analysis shows that column class, data type and program type have significant influence on RI values and, interestingly, RI values are significantly correlated to column length, column diameter, and stationary film thickness differently from theoretical properties.