title: High sensitivity steroid analysis using liquid chromatography/solvent-assisted inlet ionization mass spectrometry.
abstract: BACKGROUND
  Steroids can be injected to behave as therapeutic agents to promote muscle growth and strength. Areas of concern include synthetic steroids in consumer meat and milk products and the presence of anabolic steroids in athletes. Here we demonstrate a new ionization method for high sensitivity steroid analysis using liquid chromatography/mass spectrometry (LC/MS).
  
  
  METHODS
  Solvent-assisted inlet ionization (SAII) mass spectrometry was coupled directly to an infusion pump or to a liquid chromatograph to determine the limits of detection and quantitation for selected steroids. LC/MS/MS data was acquired on a quadrupole time-of-flight (QTOF) mass spectrometer and high resolution-accurate mass LC/MS data was obtained on an Orbitrap mass spectrometer.
  
  
  RESULTS
  The SAII limit of detection for infusion into the Orbitrap using high mass resolution and accurate mass was shown, for the steroids studied, to be low ppqt and the limit of quantitation using LC/MS was low ppt. Low ppb levels were detected with high signal-to-noise from spiked urine using a simple Ziptip procedure without sample concentration.
  
  
  CONCLUSIONS
  LC/SAII-MS is more sensitive than electrospray ionization (ESI) at similar mobile phase flow rates for the analysis of steroids. Previous studies have shown LC/SAII-MS to have high sensitivity for analysis of peptides. The combined results suggests this easy to implement ionization method may advantageously replace ESI for a wide range of analyses.
authors.affiliation: University of the Sciences, Philadelphia, PA 19104, USA.
authors.forename: Nicholas D
authors.initials: ND
authors.lastname: Chubatyi
authors.forename: Vincent S
authors.initials: VS
authors.lastname: Pagnotti
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Bentzley
authors.forename: Charles N
authors.initials: CN
authors.lastname: McEwen
mesh_terms: D045930:Anabolic Agents / Q000032:analysis; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation / Q000379:methods; D013256:Steroids / Q000032:analysis*
chemical_list: D045930:Anabolic Agents; D013256:Steroids