You need to calculate the concentration based on actual weighing done on balance (may be 2 or more decimals as per balance capacity).

Do not calculate concentration first followed by required weights as you will not get same weight on the scale due to various reasons (manual/system errors).

@Chandni Tiwari , How about amino acid analysis?

If you mean the Mt. Weight by using amino acid analysis and each amino acid weight 120 after lost the water molecular (18).

Hi Chandni!

If I understood well, you need to weight an amount of your peptide(s) that is just too small for the accuracy of your balance.

What I would do in your case is to weight an amount of your peptide ten times higher, 7.13 mg instead of 0.71 mg, and go for dilutions. So, I would weight 7.13 mg, which should be enough for an accurate measurement, and dilute it in, for instance, 100 uL (Stock 0). I would take 10 uL of those 100 uL (so you are actually taking 0.713 mg of peptide) and add them to the required amount of your buffer/solution to get the concentration you need. You can adapt all the numbers here to your own convenience, of course!

Also, I would suggest that for this first solution (Stock 0) you use milliQ water, so you can just lyophilize the rest of your peptide without purifying it again.

I hope it helps and do not hesitate to ask if you have further questions! =)

Hi,

Please check this

https://www.blueskypeptide.com/blog/properly-weigh-peptides/