title: Study on dissolution mechanism of cortisol and cortisone from hair matrix with liquid chromatography-tandem mass spectrometry.
abstract: BACKGROUND
  Hair cortisol has been used as a biomarker of chronic stress. The detected contents of hair cortisol might depend on the incubation duration in solvents for no-milled hair samples with 3-layer structure. However, there was no research on the dissolution mechanism of hair analytes.
  
  
  METHODS
  After uniform mixture, no-milled hair samples were incubated in methanol and water for the 12 different durations and milled hair was done as comparison. Hair cortisol and cortisone were determined with high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS).
  
  
  RESULTS
  The measured concentrations of hair cortisol and cortisone showed ≥2 maxima during the entire incubation in methanol and water from 5 min to 72 h for no-milled hair. Hair cortisol concentration measured by LC-MS/MS was increased with the incubation duration. Conversely, it was not held when hair was powdered prior to the incubation in methanol.
  
  
  CONCLUSIONS
  Hair cortisol and cortisone were dissolved from hair matrix through the 2-stage or multistage mechanism, which might depend on the hair 3-layer structure and its degree of damage.
authors.affiliation: Research Center of Learning Science, Southeast University, Nanjing 210096, China.
authors.forename: Xue
authors.initials: X
authors.lastname: Xing
authors.forename: Zheng
authors.initials: Z
authors.lastname: Chen
authors.forename: Jifeng
authors.initials: J
authors.lastname: Li
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.forename: Huihua
authors.initials: H
authors.lastname: Deng
authors.forename: Zuhong
authors.initials: Z
authors.lastname: Lu
mesh_terms: D000293:Adolescent; D000328:Adult; D002853:Chromatography, Liquid; D003348:Cortisone / Q000302:isolation & purification*; D006197:Hair / Q000737:chemistry*; D006801:Humans; D006854:Hydrocortisone / Q000302:isolation & purification*; D059625:Liquid-Liquid Extraction / Q000379:methods*; D000432:Methanol; D008875:Middle Aged; D012997:Solvents; D053719:Tandem Mass Spectrometry; D013997:Time Factors; D014867:Water
chemical_list: D012997:Solvents; D014867:Water; D003348:Cortisone; D006854:Hydrocortisone; D000432:Methanol