Chromatography Forum

I am trying to get my (ms) project underway, part of which will include quantifying a few metabolites in the leaves of a weed. To that end, I've purchased standards, but before injecting them willy-nilly, I figured that I'd:

1) figure out the pKa values of the compounds.
2) if the pKas are willing, choose a reagent to ionize the lot, and work up the chromatography before moving to the ms; if not, do so in different lots with different buffers.
3) of course, the solubility of the standards is (understatement) important.

Simple enough in writing, but I think that Sigma forgot to write the pKa and solubility values on the sides of my bottles.

But lo, there's... SPARC.
http://ibmlc2.chem.uga.edu/sparc/

Have you had success with SPARC? Are these sorts of calculators likely to be accurate (to) within a pKa?

Test it with a few known examples and assess it for yourself

edit: oops, you meant from the literature(!). I have done that with a few pKa values, but not enough for solubility (actually, if I remember correctly, the solubility values have been off pretty dramatically).