#68716
the inositol phosphates probably grab it pretty strongly.
for elements of group IIA of the periodic table, the trend is that as one goes down in the chart, from Be to Ba, the solubility products of chelated complexes formed from nearly all chelants decrease. inositol phosphates already have a strong affinity for Ca, Mg, as that is what IP6 is, a chelated form of Ca, Mg. I'd therefore expect the inositol phosphates would grab Ba with even more affinity than they do Ca, Mg.