Rapid Determination of Glutamine in Human Plasma by High-Performance Liquid Chromatographic-Tandem Mass Spectrometry and Its Application in Pharmacokinetic Studies

A rapid and accurate high-performance liquid chromatographic–tandem mass spectrometric method was developed and validated for the determination of glutamine in human plasma. Phenomenex EZ: faastTM amino acid analysis kit was used for sample pretreatment. Chromatographic separation was conducted on an EZ: faast amino acid analysis-mass spectrometry column (250 × 3.0 mm i.d., 4 μm). A binary gradient elution of mobile phases A (0.2% formic acid containing 5 mM ammonium acetate) and B (methanol, containing 0.2% formic acid and 5 mM ammonium acetate) was programmed at 0.4 mL/min. Multiple reaction monitoring was used for quantification by monitoring ion transitions of m/z 275.3/172.1 for derivatized glutamine and 317.3/84.1 for internal standard in the electrospray positive ionization mode. The standard curve was linear (r2 > 0.99) over the concentration range of 3.14–157.20 μg/mL. The intra- and inter-day precision values were <8.70% and the accuracy within −4.35 to 8.91% at three concentrations. The method was successfully applied to the pharmacokinetic study in Chinese healthy male subjects following oral administration of glutamine with doses of 2 and 4 g.