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How to prepare toluene solution?

  1. Jan 8, 2012 #1
    It's been a while since I last worked in the lab and I have forgotten some of the techniques in preparing solutions, especially when dealing with liquid solutes.

    I'm trying to make solution of toluene of low concentrations in the ppm levels. The specifications as shown here: http://pub.panreac.com/ds/161745IN.HTM mention that it's 99.5% pure. I would assume that this is volume per volume or mL/100mL basis since it is a liquid reagent.

    If I want to make a 100ppm (100mg/L) toluene solution how should I proceed?

    Density of Toluene: 0.8669 g/mL
    Molecular Weight: 92.14 g/mol
     
  2. jcsd
  3. Jan 8, 2012 #2
    I guess if you can't accurately measure 200 mgs for your 1 L solution you could just serial dilute something slightly heavier, say 2 g in 100 mL, take 10 mL of that, dilute with with 990 mL of solvent etc..?
     
  4. Jan 8, 2012 #3
    But I'm working with liquid toluene, so using a balance to measure mass would be bring inaccuracy to the measurement. Also how would I take into account the 99.5% spec given?
     
  5. Jan 8, 2012 #4

    Borek

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    Staff: Mentor

    How accurate do you want your concentration?

    Serial dilution won't be easy, you can't prepare concentrated solution of toluene (I am assuming you need it in water).

    Best approach is to measure a volume with a micropipette. Volume/mass/density thing.
     
  6. Jan 8, 2012 #5
    Yes, I want to dilute it in water. I don't require very high accuracy but I would like to get a proper solution for my experimental study (adsorption).

    Can you please elaborate further on "micropipette, volume/mass/density" ?
     
  7. Jan 8, 2012 #6

    Borek

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    Staff: Mentor

    So 99.5% doesn't matter - at worst your solution will be 99.5 ppm instead of 100 ppm.

    http://en.wikipedia.org/wiki/Air_displacement_pipette

    Use density and mass to find volume of the liquid you need.
     
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