Jump to content

  • Log in with Facebook Log in with Twitter Log in with Windows Live Log In with Google      Sign In   
  • Create Account

Submit your paper to J Biol Methods today!
Photo
- - - - -

Dilution Conundrum


  • Please log in to reply
2 replies to this topic

#1 Zen00

Zen00

    member

  • Members
  • Pip
  • 1 posts
0
Neutral

Posted 17 December 2018 - 04:12 PM

This should be simple but I'm just not figuring it out :/


Chemical X has a concentration of 2000 U/mL. Chemical Y has a fixed volume of 100 uL and cannot be increased or decreased in the final volume. I want a final solution with a concentration of 2 U/mL.

I naturally tend to think this could be solved by simply doing C1V1 = C2(V2 + V1), however I notice this equation will asymptotically approach infinity if your initial concentrations are similar, which means it's probably not a proper equation. So how do I figure out how much of Chemical X to add to Y to achieve my desired concentration, while taking into account the volume of X that's being introduced? Or might I be thinking of this the wrong way entirely?



#2 bob1

bob1

    Thelymitra pulchella

  • Global Moderators
  • PipPipPipPipPipPipPipPipPipPip
  • 6,668 posts
565
Excellent

Posted 18 December 2018 - 10:09 AM

If you do the calculation - you will need to add 1 ul of X to the solution to make 101 ul of final... yes, this makes an asymptote if you then go and work out the extra decimals. It'l probably end up as something like 101.11111111111...etc. It is very difficult to measure volumes below 0.5 ul consistently with ordinary lab equipment, so the margin of error comes into play.

 

Also I note the question is ambiguous - it could either be saying that you must have 100 ul of Y initially and not change this volume at all, or it could be that Y needs to be 100 ul as a final volume (i.e. 99 ul Y + 1 ul X).



#3 mdfenko

mdfenko

    an elder emeritus

  • Active Members
  • PipPipPipPipPipPipPipPipPipPip
  • 3,335 posts
213
Excellent

Posted 18 December 2018 - 02:24 PM

or that 100 ul of the final volume is y


talent does what it can
genius does what it must
i used to do what i got paid to do





Home - About - Terms of Service - Privacy - Contact Us

©1999-2013 Protocol Online, All rights reserved.