Homocitrulline with the molecular formula C₇H₁₅N₃O₃, and a molecular weight of 189.2123 daltons, can be analyzed using amino acid analysis. Molecular models for homocitrulline are shown below.

Figure 1: Structural models for homocitrulline. A: Chemical structure; B: Stick model, energy minimized; C: Space filling model.

The amino acid homocitrulline is a metabolite of ornithine in human and mammalian metabolism. The amino acid can be detected in larger amounts in the urine of individuals with urea cycle disorders. Both amino acids can be detected in urine. Amino acid analysis allows for the quantitative analysis of these amino acid metabolites in biological fluids such as urine, blood, plasma or proteins.

Figure 2: Chromatograph of a homocitrulline standard using AQC chemistry.  

Figure 3: Chromatograph of an amino acid standard including homocitrulline using AQC chemistry.

Figure 4: Chromatograph of an amino acid standard including homocitrulline. An aliquot of 100 pimoles each were injected into the amino acid analyzer column. The zoomed in region from 12 to 40 minutes of the chromatogram is shown.