A rapid and underivatized method for the determination of glutamine in human serum with ultra performance liquid chromatography-tandem mass spectrometry and its application.

A rapid and underivatized method for the determination of glutamine (Gln) in human serum was developed using ultra performance liquid chromatography tandem mass spectrometry (UPLC/MS/MS). Gln was eluted in an Acquity UPLC BEH Amid column. The chromatographic separation was performed with an isocratic mobile phase consisting of acetonitrile and ammonium formate. The analyses were carried out by select reaction monitoring using the precursor-to-product combinations of m/z 146.8→83.6 (Gln) and m/z 103.4→57.7 (IS). Validation results indicated that the lower limit of quantification was 30 μg mL(-1) and the assay exhibited a linear range of 30-600 μg mL(-1). A typical equation for the calibration curve was y = 0.0039 x + 0.0139 (r(2 )= 0.9992). The intra-batch precision (relative standard deviation, RSD) was less than 5.4% and inter-batch (RSD) was less than 9.2%, while accuracy was from 93.11 to 101.39% and from 96.22 to 99.62%, determined from quality control (QC) samples for Gln. Then the established method was successfully applied to determine the Gln concentration in the serum of healthy human and pregnant woman within three-month pregnancy. The results showed that the Gln concentration in pregnant woman serum was generally lower than the healthy human group. It suggests that the pregnant woman should eat more food packed with Gln.