Simultaneous ultra-high performance liquid chromathograpy-electrospray ionization-quadrupole-time of flight mass spectrometry quantification of endogenous anandamide and related N-acylethanolamides in bio-matrices

We describe and validate a sensitive UHPLC-ESI-QTOF-MS method for the simultaneous quantification of seven endocannabinoids and non-endocannabinoids related N-acylethanolamides: N-arachidonoylethanolamide, N-palmitoylethanolamide, N-stearoylethanolamide, N-oleoylethanolamide, N-linoleoylethanolamide, N-α-linolenoylethanolamide and N-eicosapentaenoylethanolamide in several bio-matrices for the purpose of research and clinical application. We examined effects of different liquid–liquid and solid phase extraction on the recovery of endocannabinoids and N-acylethanolamides. Protein precipitation with cooled acetone and extraction with acetonitrile (1% v/v formic acid) using OASIS HLB cartridge gave better results. Separation was performed on a Waters Acquity UPLC HSST3 column using a 9 min elution gradient coupled with high resolution mass spectrometry (QTOF/MS). The high sensitivity of the developed method allow its application on sample with low volumes or low levels of endocannabinoids and N-acylethanolamides and make the method suitable for routine measurement in human bio-matrices, such as plasma, serum (500 μL), urine (1 mL) and tissues (10–30 mg). Its application in clinical research could contribute to unravel pathophysiological roles of these family of lipid mediators and disclose novel diagnostic and prognostic markers.