1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Bradford Assay

  1. Dec 25, 2014 #1
    1. The problem statement, all variables and given/known data

    View attachment 76905
    View attachment 76906

    2. Relevant equations 3. The attempt at a solution
    Hi I have a question on Braford Assay:
    I am given this question:
    I did the caluclation as follows:
    y = 66.717x
    Since given absorbance = 0.562
    0.562 = 66.717x
    x = 0.00842ug/ul
    But the answers given is 0.168mg/ml
    I do not know what I did wrongly? Can anyone please help? Thanks!
    My answer and the correct answer differ by a factor of 20? Why is that so?
     
    Last edited by a moderator: Dec 25, 2014
  2. jcsd
  3. Dec 25, 2014 #2

    Borek

    User Avatar

    Staff: Mentor

    0.562 is not absorbance on the original solution.
     
  4. Dec 25, 2014 #3

    epenguin

    User Avatar
    Homework Helper
    Gold Member

    Yes, I was trying to answer this question but when I press your links this time I am told I don't have right to access the page. But I remember when I saw it before there was something about an 0.05 ml sample - which is 1/20 of an ml. Could these occurrences of 1/20 be in any easy connected?
     
  5. Dec 25, 2014 #4
    I still dont get it though. Sorry. I will post the image again, Sorry for the trouble pal!
    Anyway, even it is a factor of 20. My answer has a unit of ug/ul and the correct answer is in mg/ml so technically it is not a factor of 20??

    upload_2014-12-26_10-21-24.png
    upload_2014-12-26_10-21-47.png
     
  6. Dec 26, 2014 #5

    Borek

    User Avatar

    Staff: Mentor

    Please reread the last paragraph of the attached text, it clearly tells you why the difference is 20.

    50+750+200=1000.
     
  7. Dec 26, 2014 #6
    I am suppose to find the protein concentration of the liver sample what do i do with the 1000ul ?
    Is this correct?
    Since x = 0.00842ug/ul and total volume of my assay --> 1000 ul
    Then mass = 0.00842 * 1000 = 8.42 ug
    Concentration of protein = 8.42ug/50ul (of protein in liver)
    = 0.1684 ug/ul = 0.1684 mg/ml
     
  8. Dec 26, 2014 #7

    Borek

    User Avatar

    Staff: Mentor

    Correct.

    50 μl of your sample were diluted 20 times to 1000μl.
     
  9. Dec 26, 2014 #8
    Thank you!
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Bradford Assay
  1. Bradford Method Lab (Replies: 0)

  2. Bradford Assay (Replies: 3)

Loading...