sophie_paris said:

My HPLC chromatogram analysis for certificates of analysis — I sent my batch to Janoshik and here's what the results showed: Main peak retention time:…

I tested my certificates of analysis batch through Janoshik — 97.3% purity. That's within acceptable range for compounded peptides. Turnaround was 8 business days.

The test costs ~$123 but gives you actual HPLC chromatography data plus mass spec confirmation. For the peace of mind alone, it's worth every penny. I test every new batch from a new vendor.

Adding the numbers, since they settle part of this. Keep the original post as written when you update it, and add the correction underneath. An edited-away mistake is invisible to the next person who makes it.

Following on from sophie_paris — and this may be the naive question:

What did you change at the same time, and can you separate the two now?

kate.chem said:

Keep the original post as written when you update it, and add the correction underneath.

Worth saying that the confident version of this is more useful to the person writing it than to the person reading it.

kate.chem said:

Keep the original post as written when you update it, and add the correction underneath.

No disagreement, though it depends on where somebody is starting from, and this thread has been assuming a starting point nobody stated.