Thanks DWFZ.

Thinking about all this, I like shroombee's idea of the simple conversion to HCl salt. I missed that HCl is a negative azeotrope and will tend towards 20% HCl in solution as it evaporates. Starting with a mescaline citrate mass (m1), after dissolving in water, adding HCl, and evaporating, I think only mescaline HCl (m2) and citric acid (mc) will be left:

(MesH)nH3-nCit*xH2O + nHCl -> nMesHCl + H3Cit*H2O + (x-1)H2O

Where I assume citric monohydrate forms during evaporation. Also added the possibility of the starting mescaline salt being a hydrate.

We should be able to separate the citric acid mass (mc) with ethyl acetate. The ratio of MesHCl mass (m2) to citric acid mass (mc) gives n.

For each mol:

m2 ~ 247n

mc ~ 210

Taking the ratio:

n = (210/247)(m2/mc) = 0.85(m2/mc)

Where I've assumed citric acid remains as the monohydrate during ethyl acetate separation (could be wrong).

Knowing n would also tell us x since:

For each mol:

m1 ~ 211n+192+18x

mc ~ 210

Taking the ratio:

x = (1/18 ) (210*(m1/mc) -211n - 192)

So shroombee's suggestion may allow us to fully characterize the mescaline citrate salt form. If after measuring m1, m2, and mc we experimentally get integers for n and x confidence would be high.

I started testing this but made the mistake of using heat to speed up evaporation. Turns out that citric acid breaks down with heat (175C) and started to make a mess. Gonna try again with slow room temp evap (will take a few days).