Investigation of General Expression to Predict the Molar Response Factor in the GC for Monosubstituted Alkanes

The flame ionization detection relative molar response factors (fM) are determined by experiments for 23 monosubstituted alkanes RX (X=Cl, OH, SH, and NH2). A new molecular descriptor, modified inner molecular polarizability index (IMPIm), is developed. Using the IMPIm, the number of hydrogen atoms (NH) on the group X and the group electronegative Xp as variables, the obtained fM values as functions, a general expression to predict molar response factor values, is established. The credibility of the expression is confirmed by both of the leave-one-out method and the detection of model mixture.