Ionization - pKa

pION uses industry standard methods for measurement of ionization constants (pK_a). We can analyze up to 10 overlapping pK_a and can distinguish protogenic counter-ions. Sparingly soluble compounds may be analyzed in mixtures of an organic solvent (such as methanol or DMSO) and the aqueous pK_a extrapolated.

Our potentiometric and spectrophotometric methods have measured pK_a values as low as 1.0 and as high as 13.0. Using standard potentiometric procedures, we routinely measure pK_a between 2.0 and 12.0 for compounds not requiring a cosolvent and between 3.0 and 11.0 for compounds whose aqueous pK_a is extrapolated from cosolvent mixtures. If compound structure is appropriate, the spectrophotometric method is applied to measure pK_as of water soluble and insoluble compounds between 2.0 and 12.

• Fill out a Sample Submission Form for EACH compound.  Also, fill out the Sample Input Template (enter all samples), and send a printout with the samples to pION
• Please include the Purchase Order number on the sample submission form
  
• For optimal measurements, send 7-10 mg.
  
• For aqueous pK_a measurements, it is recommended that your sample is soluble at >100 µg/mL from pH 3.0-11.0.