A simple LC-MS/MS method for the determination of cortisol, cortisone and tetrahydro-metabolites in human urine: Assay development, validation and application in depression patients

- A LC-MS/MS method for simultaneous determination of F, E THF, 5α-THF and THE in human urine has been developed and validated.
- The nocturnal urine concentrations of F, E THF, 5α-THF and THE in healthy adults and depression patients were analyzed.
- The procedure of sample preparation was simple.
- The real human urine was used in the method validation.