The cleavage cocktail is composed of Phenol/thioanisole/water/TFA/triisopropylsilane. I only prepare 10 mL cocktail per peptide but can the activity of the cocktail prepared at 100 mL last for a week?
Hi Simon, I have used many cleavage cocktails and scavangers for peptide cleavage. My opinion: The cocktails aren't that stable, especially the TIPS and thioanisol. Maybe one week is fine if you keep it in the freezer. I would recommend to start with a fresh cocktail each day for best results.
I like to prepare the cocktail fresh every time since an inefficient cleavage complicates purification and lowers yields, so why take the chance?
The components are immiscible and therefore difficult to dispense equally into smaller portions: that's why we call it a cleavage cocktail and not a cleavage solution. I wouldn't expect the cocktail to stay fresh for long since it's reactive and prone to oxidation by air. If you insist on preparing a large batch though, I would try degassing the solution with nitrogen or argon bubbling, split it into 10 mL portions, then store them in the freezer. Thaw aliquots on an as-needed basis. To be sure this works, you would have to compare the results from the thawed cleavage cocktail with a fresh batch. I don't know about you, but I'd rather not keep such a nasty mix in my freezer, so I'll keep preparing my solutions fresh.
Hello Simon Miguel Lopez! In my opinion, the best is to always use a freshly prepared cocktail. Just to avoid asking myself: what happened? when something went wrong with the cleavage. Despite the handling of those chemicals, I even prepare it every time in a day I need it. Regarding the mixing issue, you can always stir it for a couple of minutes, and you may be lucky and have a solution instead of the cocktail ;-) Good luck!
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