Prediction of gas chromatographic retention indices using variable connectivity index

We have re-examined gas chromatographic retention indices of alkanes (48 compounds), and alcohols (31 compounds), combining all molecules into a single set (n=79) using variable connectivity index ¹χ^f. By varying the weight for oxygen atom we obtained the regression characterized by the correlation coefficient r = 0.9933, the standard error s=14.24 retention time units, and Fisher ratio F = 5695. Use of the simple connectivity index ¹χ, which does not differentiate carbon and oxygen atoms, gives regression with the standard error four times larger.