Food tests: Benedict's (quantitative vs qualitative)

Discussion in 'Supporting Biology' started by Jimbob1988, Jul 4, 2019.

  1. Morning all,

    With regards for the tests for reducing sugars, can one use either Benedict solutions?

    Many thanks,

    Samuel
     
  2. Depends what you want it to do

    Qualitative will tell you if there are any in your sample and nothing more
    Quantitative will obviously tell you if any is there but it's also calibrated to tell you how much is there compared to other samples

    If you're only looking for a confirmatory test then use either, if they need to know how much is there then use quantitative
     
  3. If it is for KS3 or KS4 I would use qualitative. They just need to know the positive result, which is usually quoted as being an orange/red colour. We use quantitative at KS5, when heated you get a white precipitate and so use a colorimeter to measure the differences.
     
  4. Positive from qualitative ranges from green through yellow to brick red.

    Regarding quantitative, I've been trying to get a definitive answer to this: do you use the colorimeter on the suspended precipitate or on the settled/filtered remains?
     
  5. You should filter both but AQA don't mention it.