missing microspecies from pKa prediction

User 9cc9c09363

01-03-2016 19:56:47


Could you please let me know the reason why the calculator gives 7 microspecies for cetirizine which has three dissociation/protonation sites so we are supposed to have 8 microspecies ?


Thank you for your answer in advance.




ChemAxon 2136dd2f4b

02-03-2016 14:28:45


Only those of microspecies are displayed which have at least 0.01% contribution to the total amount of the different micro forms.The % distribution of the missing 8th microspecies is too low to show.

There is no user-option available (now) to change the threshold value 0.01%.


User 9cc9c09363

02-03-2016 15:15:34

Great. Thanks for the answer!