title: Two-step derivatization procedures for the ionization enhancement of anabolic steroids in LC-ESI-MS for doping control analysis.
abstract: BACKGROUND
  Two-step derivatization procedures were developed for the enhancement of the positive ESI in LC-MS detection of anabolic androgenic steroids, a class of prohibited substances with limited ionization efficiency in atmospheric pressure interfaces. The developed procedures are based on the esterification of hydroxyl groups of anabolic steroids with picolinic acid, followed by conversion of carbonyl groups to Schiff bases by either Girard's reagent T or 2-hydrazino pyridin.
  
  
  RESULTS
  Ionization efficiency for the model derivatized compounds 19-norandrosterone (nandrolone main metabolite) and methasterone was higher by almost two orders of magnitude compared with the respective efficiency of the underivatized compounds.
  
  
  CONCLUSIONS
  The obtained derivatives provided a significant improvement in the ESI sensitivity, compared with those of underivatized molecules in positive LC-ESI-ion trap-MS full-scan mode.
authors.affiliation: Doping Control Laboratory of Athens, Olympic Athletic Center of Athens, Kifissias 37, 15123 Maroussi, Greece.
authors.forename: I
authors.initials: I
authors.lastname: Athanasiadou
authors.forename: Y S
authors.initials: YS
authors.lastname: Angelis
authors.forename: E
authors.initials: E
authors.lastname: Lyris
authors.forename: A
authors.initials: A
authors.lastname: Vonaparti
authors.forename: N S
authors.initials: NS
authors.lastname: Thomaidis
authors.forename: M A
authors.initials: MA
authors.lastname: Koupparis
authors.forename: C
authors.initials: C
authors.lastname: Georgakopoulos
mesh_terms: D045930:Anabolic Agents / Q000737:chemistry / Q000652:urine*; D002853:Chromatography, Liquid / Q000379:methods*; D004300:Doping in Sports / Q000517:prevention & control*; D005260:Female; D006801:Humans; D008297:Male; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D015813:Substance Abuse Detection / Q000379:methods*
chemical_list: D045930:Anabolic Agents