Where:
RTgmpA: retention time of GMPA in the scouting gradient,
10: the initial % B of the scouting gradient,
2,5: % B at midpoint minus % B at initial in the normal gradient,
13,5: midpoint time of the scouting gradient,
26: required retention time of GMPA,
6: ratio of slopes of the scouting and normal gradient,
30: % B at initial minus % B at 27 minutes in the scouting gradient,
27: run-time of the scouting gradient.
