September 22, 2024, 01:30:49 PM
Forum Rules: Read This Before Posting


« previous next »
Pages: [1]   Go Down

Topic: Measuring partition coefficient and getting values much less that cited values  (Read 2130 times)

0 Members and 1 Guest are viewing this topic.

Offline dun13203171

  • Regular Member
  • ***
  • Posts: 76
  • Mole Snacks: +0/-0
Measuring partition coefficient and getting values much less that cited values
« on: April 03, 2016, 05:08:37 PM »
Hi guys,
            I was working in the lad, seperating a weakly acidic drug between who immicible liquids and I am getting a log p value of 0.15 and the cited value of 1.7.

I have repeated the experiment 3 times and still get roughly the same value, anyone any ideas why it is so far of what it should be?

thanks
Logged

Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 27793
  • Mole Snacks: +1807/-411
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
Re: Measuring partition coefficient and getting values much less that cited values
« Reply #1 on: April 03, 2016, 05:12:58 PM »
pH?
Logged
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info

Offline dun13203171

  • Regular Member
  • ***
  • Posts: 76
  • Mole Snacks: +0/-0
Re: Measuring partition coefficient and getting values much less that cited values
« Reply #2 on: April 04, 2016, 04:37:22 PM »
pH's should be buffered correctly. Anything else you can think of?

Also, just to confirm.

If you added 10ml of 0.1M HCl to 10ml water and added to 20ml octanol, the resulting pH would be 1.3? conc of H+ of 0.05 moles, -log(H+)=1.3

Starting to question myself.
Logged

Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 27793
  • Mole Snacks: +1807/-411
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
Re: Measuring partition coefficient and getting values much less that cited values
« Reply #3 on: April 05, 2016, 02:51:32 AM »
Quote from: dun13203171 on April 04, 2016, 04:37:22 PM
If you added 10ml of 0.1M HCl to 10ml water and added to 20ml octanol, the resulting pH would be 1.3? conc of H+ of 0.05 moles, -log(H+)=1.3

A bit different from 1.3 as it depends on the ionic strength of the solution, but the difference won't be large (several tenths at most).
Logged
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info
Pages: [1]   Go Up
« previous next »
Sponsored Links