Allow collecting multiple target components in a single fraction.

[ronald-jaepel]

This isn't really a bug, more a documentation of an unexpected implicit behavior we found that took a bit to understand. Maybe it's documented somewhere, but I didn't find it.

When using the Fractionator and evaluating fractionator.mass, this only returns a subset of the mass stored in these fractions.

A given example from G.P. with three components (Salt and two charge variants of a Protein (simulated as Protein A and Protein B)), of which both charge variants are components of interest and we want to collect both in one fraction.

Using the fractionator to collect into our first sample with

fractionator = Fractionator(simulation_results, components=['A','B'])
fractionator.add_fractionation_event(
  event_name='Elution', 
  target=0, 
  time=elution_start_time, 
  chromatogram='outlet'
)

and calling fractionator.mass, I would expect to get a 2x1 array containing the masses of Protein 1 and Protein 2 in our single fraction (α & β in the table below), because I've only created one fraction.

	Protein A	Protein B
Fraction 1	α	β
Fraction 2	γ	δ

Instead, I get α & δ, because the fractionator implicitly assumes that each component will be collected in their own fraction pool.

We got the info we wanted with fractionator.fraction_pools[0].mass.

[schmoelder]

Thanks for your feedback. I think I understand the issue, however, this is currently not supported.

Do you have an idea how we would could configure the Fractionator to allow this behavior?