Jul 02, 1989 · 10,000 g. A volume of 120 L was transferred into the GC vial with an insert (250 L pulled point glass Aijiren Technologies, Santa Clara, CA, USA) (see Figure1). Metabolites 2017, 7, 19 3 of 8 2.3. Calibration Lines of 3-HB Sodium 3-hydroxybutyrate (95.2% purity) was purchased from Sigma Aldrich (Darmstadt, Germany).