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

Abstract: Objective: To develop a method for simultaneously determining l-citrulline and l-arginine levels in plasma using RP-HPLC with ultraviolet detection. Design and methods: Plasma samples were deproteinized by trichloroacetic acid and heat. Phenyl-isothiocyanate (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 1000μmol/L. R2 values were above 0.9999 for both. LODs for l-citrulline and l-arginine were 0.0201μmol/L and 0.0476μmol/L, respectively, while LOQs were 0.240μmol/L and 0.448μmol/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±9.18μmol/L and 58.19±16.43μmol/L, respectively. Conclusion: This approach offers a reliable, efficient analytical platform for the simultaneous determination of citrulline and arginine levels in plasma. [ABSTRACT FROM AUTHOR]