Plasma Metabolite Profiling by GC-MS

The extracted samples were chemically derivatized via the methyl chloroformate (MCF) method based on the recommendations published by Smart et al. [20 (link)]. All cord plasma samples were analyzed in a single batch and derivatized compounds were examined by an Agilent GC7890B system using a ZB-1701 GC capillary column. An MSD5977A mass selective detector with the electron impact voltage set to 70 eV was applied to analyze the compounds. The GC column used for metabolite separation was the ZB-1701 GC capillary column (30 m × 250 μm id × 0.15 μm with a 5 m guard column, Phenomenex). The GC temperature was set up according to the protocol of Han et al. [21 (link)].