L-Citrulline-1,2,3,4,5-¹³C₅

This certified reference material (CRM) is produced and certified in accordance with ISO/IEC 17025 and ISO 17034. This CRM is traceable to the SI through a primary reference material from an NMI, e.g. NIST, NRC or NMIJ.


Certified content incl. uncertainty and expiry date are given on the certificate.


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Citrulline is a non-proteinogenic amino acid produced in the urea cycle and during nitric oxide synthesis, often used as a biomarker of enterocyte (intestinal) mass and function. Testing citrulline can help assess conditions like short bowel syndrome, mucosal injury from chemotherapy or radiation, and some urea-cycle disorders, supporting both clinical evaluation and research. Accurate measurement commonly uses LC–MS/MS, where a stable isotope–labeled citrulline acts as an internal standard to correct for extraction losses, matrix effects, and instrument variability. Because the labeled standard is chemically identical and co-elutes with native citrulline, it enables robust calibration and improves accuracy, precision, and inter-lab comparability. This leads to more reliable decisions based on citrulline levels.





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