title: Profiling phospholipid elution in reversed-phase LC-MS/MS bioanalytical methods in order to avoid matrix effects.
abstract: BACKGROUND
  Endogenous phospholipids have a profound matrix effect in bioanalytical LC-MS methods and considerable effort is invested in strategies to minimize their impact either by removal during sample processing or chromatographic separation during the analytical run. The aim of the research presented in this article was to investigate the latter approach, under reversed-phase conditions.
  
  
  RESULTS
  The retention of glycerophosphocholines (GPCs) in mobile phases employing acetonitrile demonstrated a complex 'U-shaped' relationship with the percentage of organic. Conversely, in mobile phases employing methanol, the relationship between retention and percentage of organic was entirely predictive and unaffected by changes in the mobile phase pH. The GPC elution profile was also qualitatively equivalent irrespective of the species from which the plasma was derived.
  
  
  CONCLUSIONS
  The predictive nature of GPC retention, under reversed-phase chromatography and with MeOH as organic modifier, is an important finding that should allow for a more streamlined and simplified strategy in the development of bioanalytical assays.
authors.affiliation: Department of Clinical Pharmacology & DMPK, AstraZeneca R&D, Charnwood, Bakewell Road, Loughborough, LE11 5RH, UK. stephen.silvester@astrazeneca.com
authors.forename: Steve
authors.initials: S
authors.lastname: Silvester
authors.forename: Luke
authors.initials: L
authors.lastname: Smith
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D000818:Animals; D056148:Chromatography, Reverse-Phase / Q000379:methods*; D004285:Dogs; D005997:Glycerylphosphorylcholine / Q000032:analysis / Q000097:blood* / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D000432:Methanol / Q000737:chemistry; D051381:Rats; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D000097:Acetonitriles; D005997:Glycerylphosphorylcholine; D000432:Methanol; C032159:acetonitrile