title: Troubleshooting in LC-MS/MS method for determining endocannabinoid and endocannabinoid-like molecules in rat brain structures applied to assessing the brain endocannabinoid/endovanilloid system significance.
abstract: BACKGROUND
  In recent years, a potential participation of endocannabinoids (eCBs) and related endocannabinoid-like molecules, including N-acylethanolamines (NAEs), in the physiological and pathophysiological processes has been highlighted, whereas measurement of their levels still remains difficult. The aim of this study was to develop a bioanalytical method that would enable researchers to simultaneously determine quantitatively eCBs (anandamide - AEA and 2-arachidonoylglycerol - 2-AG) and NAEs (oleoylethanolamide or oleoylethanolamine - OEA, palmitoylethanolamide or palmitoylethanolamine - PEA and linoleoylethanolamide or linoleoylethanolamine - LEA) in the rat brain. The analytical problems with analysis and possible solutions have been also shown.
  
  
  METHODS
  The methodology for quantifying eCBs/NAEs by means of a sensitive and selective liquid chromatography tandem mass spectrometry (LC-MS/MS) with electrospray positive ionization and multiple reaction monitoring (MRM) mode was developed and validated. Analytical problems with analyzed compounds were estimated.
  
  
  RESULTS
  Reasonably high precision and accuracy of the method were demonstrated in the validation process. The method is linear up to 200 ng/g for AEA, OEA, PEA and LEA and up to 100 μg/g for 2-AG, while the quantification limit reaches 0.2 ng/g and 0.8 μg/g, respectively.
  
  
  CONCLUSIONS
  Simplicity and rapidity of the assay allows analyzing many samples on a routine basis. This article presents the new procedure applied to the analysis of brain tissues.
authors.affiliation: Department of Toxicology and.
authors.forename: Beata
authors.initials: B
authors.lastname: Bystrowska
authors.forename: Irena
authors.initials: I
authors.lastname: Smaga
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Tyszka-Czochara
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Filip
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D002138:Calibration; D002853:Chromatography, Liquid / Q000379:methods*; D063388:Endocannabinoids / Q000378:metabolism*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D063388:Endocannabinoids