Determination of glycine in body fluids at trace levels using the combination of quadrupole isotope dilution strategy and Liquid Chromatography-Quadrupole Time of Flight-Tandem Mass Spectrometry

Abstract

In this study, Quadrupole Isotope Dilution Mass Spectrometry (ID4MS) strategy was coupled with Liquid Chromatography-Quadrupole Time of Flight-Tandem Mass Spectrometry (LC-QTOF-MS/MS) for the accurate and precise determination of glycine in body fluids at trace levels. The instrumental variables such as column temperature, injection volume, sample/gas flow rates, fragmentor/capillary voltages, were optimized. Under the all optimized conditions, the calibration plot of glycine demonstrated a linearity ranging 5.0–100 mg kg−1 and, the detection and quantification limits were obtained as 1.4 and 4.7 mg kg−1, respectively. Superior enhancement was achieved for the accuracy and precision of proposed method when combined with ID4MS strategy. Percent recoveries of the proposed method for human plasma and urine spiked at 80 mg kg−1 were calculated as 99.72 ± 0.54% and 100.91 ± 1.32%, respectively. These results validated the applicability of the method to complex matrices as well as confirming the high accuracy and precision.