Rapid determination of [guanidino-15N]arginine in plasma with gas chromatography--mass spectrometry: application to human metabolic studies.
A rapid gas chromatographic-mass spectrometric method for the determination of 15N in the guanidino nitrogens of arginine is described. The method is based on formation of the N-tetratrifluoroacetyl-arginine derivative. Approximately 0.15 mol% excess 15N can be detected in as little as 50 microliters of plasma with an average coefficient of variation of 8.8%. The possible fragmentation pattern of the N-tetra-trifluoroacetyl-arginine derivative is described. The method was applied to determine the appearance of 15N enrichment in plasma arginine in a healthy adult volunteer during a constant infusion of 15NH4Cl. A plateau level of 0.7 atom% excess was observed 2 h after the 15NH4Cl infusion was started.
D000089:Acetic Anhydrides; D000643:Ammonium Chloride / Q000008:administration & dosage; D001120:Arginine / Q000097:blood / Q000378:metabolism*; D005463:Fluoroacetates; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007201:Indicator Dilution Techniques; D007263:Infusions, Parenteral; D009587:Nitrogen Isotopes
D000089:Acetic Anhydrides; D005463:Fluoroacetates; D009587:Nitrogen Isotopes; D000643:Ammonium Chloride; C017958:trifluoroacetic anhydride; D001120:Arginine