Usually your peptide is isolated as an amorphous powder, which has been lyophilized from the diluted trifluoroacetic acid (TFA) solution. It is generally very difficult to weigh the hygroscopic peptide powder accurately. In addition, the weight of your peptide is the sum of the actual peptide with other constituents such as TFA and water, which may affect the result of your experiment due to the net peptide content sometimes being diminished to 60-70% of the weight on the balance. For the precise experiment, we offer the optional dispensing service: preparation of equal volume of aliquots of your peptide solution in 30-50 injection vials, lyophilyzation, and determination of the net peptide content (excluding TFA and water) in each vial. The peptide content in each vial is accurately measured, therefore, you can prepare your peptide solution of known concentration readily by injecting the appropriate solvent into a vial using the calibrated syringe and dissolving the content thoroughly. Thus, you may avoid the difficulties of weighing the lyophilized product.