schulze's solution

pkij · Post by **pkij** » 06 Mar 2007, 15:24

I have a prac which requires schulze's solution for the identification of cellulose. I cant seem to find any references to how it is made or how to use it. Can anyone help?

jojo · Post by **jojo** » 06 Mar 2007, 15:34

Hi pkij

I found this but have not used it. Hope it works for you.
Schulze's solution (chlor-zinc-iodine)
Dissolve 20 g zinc chloride in 9.5 mL warm water. Cool, add drop by drop 1.5 mL of the following solution until a persistent precipitate of iodine forms: 0.5 g iodine, 1 g potassium iodide, 20 mL distilled water.

jojo

JudyM · Post by **JudyM** » 07 Mar 2007, 08:51

I have much the same recipe as Jojo only 8.5ml water is used instead of 9.5ml.
The ppt. should persist on shaking. Pink/purple indicates a positive result.

An alternative is Cross & Bevan's reagent:
2 parts conc. HCl to 1 part zinc chloride crystals by weight.
(From my "bible" - A Handbook of Laboratory Solutions by Gabb & Latchem)

Cheers

lizzieb · Post by **lizzieb** » 07 Mar 2007, 08:59

I had this same request, and found the same old handwritten recipe as Jojo, which has not been used here in the last 7 years, at least.

Some of the other staff suggested using Sudan lll instead, which we use regularly.

Liz

JudyM · Post by **JudyM** » 07 Mar 2007, 09:30

Hi Lizzieb,

Does Sudan 111 really work as an indicator of cellulose?

I thought that it was used as a fat stain only.
Can you give me more info please.

Cheers
Judy

Jazz · Post by **Jazz** » 07 Mar 2007, 10:24

hi,
we use conc sulfuric acid (73mL H2SO4 and 27mL water) to break cellulose down to starch and then use iodine/potassium iodide test for starch

lizzieb · Post by **lizzieb** » 07 Mar 2007, 12:07

Hi Judy,

Thanks for pointing that out! I was going on what the staff said, having not heard of Schultz's solution before.

My reading up this afternoon agrees with you, Judy, so sorry if I've led anyone astray. It's sport now, but I will ask for clarification tomorrow!

Just illustrates again why this web-site is so valuable...

Cheers,
Liz

lizzieb · Post by **lizzieb** » 07 Mar 2007, 13:09

OK, have sorted that - must have confused the staff when I asked earlier.

(Will just go back to my washing-up, now - can't get too mixed-up with that)

Guess what I'll be making tomorrow!

Thanks again, guys. You're my best resource!

Liz

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schulze's solution

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Schulze's Solution

Schulze's solution