2.4 UHPLC-MS/MS analytical conditions
The method to analyze TGC in bio-samples has been described in previous
review[11]. Relative method was optimized in our
study. The chromatographic system was consisted of an AB SCIEX QTRAP®
4500 triple-quadrupole
mass-spectrometric system (AB Sciex, MA, USA) coupled with an ultrafast
liquid chromatography (AB Sciex, MA, USA). Separation was performed on a
Waters XBridge® BEH Shield RP18 column (3.0×50mm, 2.5μm) from Waters
Corporation, USA. The temperatures of auto sampler and column oven were
15°C and 40°C respectively. The mobile phase was composed of aqueous
mixed with 10 mM ammonium formate (pH=2.5) and acetonitrile according a
gradient volume ratio (100:0→10:90→100:0), and pumped at 0.3 mL/min.
Quantitative analysis of TGC was processed utilizing positive electron
spray ionization in multiple reaction monitoring mode at m/z 586.3→513.2
and 586.3→456.2. TGC-d9 was monitoring in the channel of 595.1→514.2.
Mass spectrometer parameters for identification of TGC and TGC-d9 were
summarized in Table 1.