Simultaneous determination of L-citrulline and L-arginine in plasma by high performance liquid chromatography

Objective: To develop a method for simultaneously determining L-citrulline and L-arginine levels ill plasma using RP-HPLC with ultraviolet detection. Design and methods: Plasma samples were deproteinized by trichloroacetic acid and heat. Phenylisothiocyanate (PITC) solution was used as derivatization reagent and a gradient elution was carried out. Results: The linearity for L-citrulline and L-arginine ranged from 0 to at least 1000 mu mol/L. R-2 values were above 0.9999 for both. LODs for L-citrulline and L-arginine were 0.0201 mu mol/L and 0.0476 mu mol/L, respectively, while LOQs were 0.240 mu mol/L and 0.448 mu mol/L, respectively. Intra- and inter-day CVs were less than 3.40% and 7.2%, respectively. The average recovery was from 86.22% to 118.9%. L-Citrulline and L-arginine concentrations in healthy controls were 60.77 +/- 9.18 mu mol/L and 58.19 +/- 16.43 mu mol/L, respectively. Conclusion: This approach offers a reliable, efficient analytical platform for the simultaneous determination of citrulline and arginine levels in plasma. (C) 2010 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.