For GMP-products the analyses are run in duplicate, so that homogeneity of the sample is examined, weighing errors and problems during sample preparation or chromatography will be eliminated. OOS can be defined by an unusual standard deviation of the results of both analyses. If the customer would like to run only a single analysis it should be noted on the order.

Due to the analyses in duplicate a mean value of results can be calculated. We give a 10% discount on both analyses.

Analyses in duplicate are recommended for quantitation

• of the main product (eg AAA if peptide content is required) to calculate the mean value of the results and to be able to exclude a weighing error. The result could be also verified by eg. mass balance (eg. content of peptide + water + counter ion + residues of solvents ~ 100%).
• water and acetate/TFA to exclude weighing error and inhomogeneity
• residues of solvents to prove the homogeneity of the sample
• determination of enantiomeric purity via GC-FID to prove that the amino acid racemize during sample preparation in the range of the standard deviation of the method. Unexpected racemization will usually be indicated by higher standard deviation. In addition the homogeneity of the sample is proved.