Comparison of the simulated (a) tracer, (b) ester and (c) alcohol outlet concentration profiles obtained with the first-order scheme and the highest spatial resolution n = 16 with the ones obtained with the second-order schemes O(2^m) and O(2^s), with the spatial resolutions n = 4 and n = 2 that approximately match the profiles, respectively. This figure shows that the and profiles approximately frame the profile: therefore, the O(2^m) and O(2^s) schemes reproduce the O(1) profiles with approximately 4 to 8 times less cells, respectively.