C.A.T. GmbH & Co. Chromatographie und Analysentechnik KG

Heerweg 10
D-72070 Tübingen

Phone: +49 (0) 7071 / 78323
Fax: +49 (0) 7071 / 75163

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General Information > analyses in duplicate


Analyses in duplicate

Analysis of products required to conform with GMP is routinely performed in duplicate. Thus we can check the homogeneity of the sample and recognize errors in weighing and/or problems associated with the sample preparation or the chromatographic separation. OOS (Out Of Specification) can be defined by an unusual standard deviation of the results of both analyses. If, on the other hand, a single analysis is preferred, this should be noted explicitly when ordering.

Analysis in duplicate allows us to calculate a mean value of results. For duplicate analyses we offer 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 any weighing error. The result can be also verified eg. by mass balance (ie. content of peptide + water + counter ion + residues of solvents should equal 100%).
  • for quantitation of water and acetate/TFA to exclude weighing errors and inhomogeneity
  • for quantitation of residues of solvents to confirm the homogeneity of the sample
  • for the determination of enantiomeric purity via GC-FID to confirm that the racemization of amino acid residues during sample preparation lies within the range of the standard deviation of the method. Higher standard deviation is an indication either sequence-dependent racemization or inhomogeniety of the sample.


regularly inspected by FDA and German Authorities

GMP approved