July 22, 2024, 04:51:11 PM
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Topic: Peptide with purple coloration in solid phase peptide synthesis  (Read 987 times)

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Offline veno

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Peptide with purple coloration in solid phase peptide synthesis
« on: December 15, 2022, 06:11:26 PM »
Any idea why my peptide ends up with a purple color when cleavaged and precipitates into ether?

It is a peptide of 34 amino acids and I use as a cleavage cocktail 94% TFA/2.5% water/2.5 thioanisol/ 1% TIS for 2 hours.

Offline MOTOBALL

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Re: Peptide with purple coloration in solid phase peptide synthesis
« Reply #1 on: December 16, 2022, 07:16:08 PM »
Can you extract the purple colour into an organic solvent? (Prefer MeCn).

If so, scan the UV spectrum and determine lambda max as a first step.

Also, run an LCMS to determine [M+H]+ for Mol. At.

Then run MS/MS on the [M+H]+ ion to help elucidate structure.

Identification will help understand where it comes from.

Regards,
Motoball

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