Yes, but you do need to redissolve the whole sample first. Be sure that everything is fully dissolved. Ensure that the sample is really frozen before the application of vacuum and that there are no vacuum interruptions during during drying - for example, if you are using a public machine in a lab, when another user adds their samples, this can cause vacuum level to increase, and your sample to "melt back". If this is late in the drying process you will get a very concentrated wet droplet which is unlikely to freeze well.

I appreciated. I did exactly as you mentioned, dissolve completely first, freeze, and then lyophilize. However after a day on the lyophilization, I got a very tiny wet portion of chunk that couldn't break it to powder.

I think I did a mistake by removing from the lyophilize, and I should leave it longer to dry completely for other hours or a day as you stated "this can cause vacuum level to increase, and your sample to "melt back". If this is late in the drying process you will get a very concentrated wet droplet which is unlikely to freeze well".

thank you for the explanation

The freeze-dried product absorbs moisture very easily, you can put it back immediately and freeze-dry it once again. However, I am sorry to say that this may not always be successful. Because at room temperature, the structure of the lyophilized product may have been destroyed. Good luck. Next time you can lyophilize for a longer time or make a small sample to check.

Hi Danli,

I lyophilized two of samples again, but the issue is that I am not getting the right amount of weight for all four samples, whether it was lyophilized once or twice. I kept the synthesized peptides in -200 C, left them at RT for 1hr, and finally weighed each of my samples after taring between them. All my samples should weigh less than 1 g, and I am getting more than that.

I don't know where a mistake is.

Thank you for time