In the Titration of amino acids Glycine and Lysine

Question

Which data can be obtained with greater accuracy?

1.the pK values from the "legs" ?
2.the isoleric point from the point of inflection?

Answer 1

I would think the pK values. My experience, anyway, is that the inflection is hard to pin-point, even by making a second derivative plot.

Answer 2

Thank you DrBob

It makes sense since the PI(point of inflection)is calculated by adding the two pk values and dividing it by 2...Pk1/2+ Pk2/2= PI