As adjectives, not in a math context: 'different' vs 'differential'
"Differential" is a compact way of saying "difference between the" (or its equivalent).  For instance, in your first example, where the author writes "Chromatographic separations result from the differential interactions of the enantiomers...", what's meant is  "Chromatographic separations result from the difference between the interactions of the [two] enantiomers...".  

I.e., chromatographic separation results from the fact that there is a difference between how the two different enantiomers react with the stationary phase (the solid column packing material).

The first definition given in your link applies here: "Of, showing, or depending on a difference; varying according to circumstances or relevant factors."