Updated Nov 20, 2015
HPLC analysis will tell you what percentage of the peptide material consists of target peptide – this is what one refers to as the purity of a peptide. An analysis such as the elemental analysis will on the other hand say what percentage of the lyophilized peptide powder is peptide material – this is what is called net peptide content. If you need to know how much target peptide is in a given amount of powder, you need to know both peptide purity as well as net peptide content.
The industry standard is to supply synthetic peptides as a lyophilized powder and to state amounts as the weight of this powder. The powder consists of peptide material, counter ion, and bound water. Thus, when you order 10 mg of peptide, you order 10 mg of peptide powder, but the net amount of peptide will be less. In most cases this is not an issue, but it is something one should be aware of.
Net peptide content depends on amino acid sequence, but in general the net peptide content is 60-90%. There are two methods widely employed to determine the net peptide content. Amino acid analysis, (AAA), and elemental analysis (CHN). AAA only requires minimal amounts of peptide while CHN consumes milligrams of peptide. CHN analysis on the other hand is far more accurate. In fact, it may be debated whether or not AAA is much better than making an educated guess. Since not knowing the net peptide content seldom is an issue, an analysis is seldom made. On those occasions when knowing the net peptide content actually does make a difference then the accuracy that AAA offers might not suffice.
Innovagen was founded in 1992. In these 20 years or so, we have accumulated a great deal of experience in the field of antibody and peptide production. The single most valuable lesson has been that quality always pays off. As a result we are committed to providing excellent quality and customer service.
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