All materials supplied to LifeTein are considered the confidential property of the customer. LifeTein provides free HPLC and MS results with your package. Peptides are purified by reverse-phase chromatography. The chromatogram indicates the number and relative amount of by-products. The molecular mass of the peptide is determined by mass spectrometry to confirm that the correct product is being delivered. MS results also show the masses of the main impurities. Additional analysis revealing net peptide content can be performed upon request. Net peptide content is indicated by either amino acid analysis or elemental analysis. These methods allow the verification of the amino acid composition of the peptides. They serve as additional means of confirmation of peptide identity. All synthetic peptides meeting the customer's purity criteria are sent. All residual materials, such as peptides not meeting the customer's purity criteria are discarded. These residual materials can be sent to the customer upon request.