Blood levels of ketamine and its metabolites
BLOOD
Venous blood samples were taken from the non-infusion arm at 8, 13, and 48 min after the beginning of the infusion. Blood samples were kept on ice, processed, and freezed within 2 h after the sampling. The samples were analyzed with liquid chromatography hyphenated targeted mass spectrometry for the simultaneous analysis of ketamine (KET), and norketamine (NK (for details, see