Development of UHPLC–MS/MS method for determination and quantification of endocannabinoids in cerebrospinal fluid

Abstract

AbstractEndocannabinoids (eCBs) are endogenous lipids that activate cannabinoid receptors. Their role in neuroinflammation is of a great interest due to the range of physiological effects they exhibit, potentially serving as bioindicators of pathologies. However, they are present at nanomolar concentrations in biological samples, posing challenges for detection and quantification. A method for quantitative analysis of eight exogenous eCB internal standards (anandamide-d4, docosahexaenoyl ethanolamide-d4, eicosapentaenoyl ethanolamide-d4, linoleoyl ethanolamide-d4, oleoyl ethanolamide-d4, palmitoyl ethanolamide-d5, stearoyl ethanolamide-d3 and palmitanilide) in cerebrospinal fluid is reported here. Six monophasic solvents (methanol, acetonitrile, chloroform/methanol/water, acetonitrile/acetone, isopropanol/acetonitrile/water, and ethanol) were compared in their extraction efficiency. Detection of analytes was performed using an ultra-high performance liquid chromatography method coupled to tandem mass spectrometry (UHPLC-MS/MS) in dynamic multiple reaction monitoring (dMRM) mode. The method was further optimised based on accuracy, precision, matrix effect, linearity, limits of detection and quantification. The method was applied to a cohort of healthy individuals (n=33) to identify and estimate the concentration of eCBs in CSF.