LC-MS/MS Quantification of Endocannabinoids in Tissues

Endocannabinoids (ECBs) are lipid-derived endogenous molecules with important physiological roles such as regulation of energy balance, immunity, or neural development. Quantitation of ECBs helps better understand their physiological role and modulation of biological processes. This chapter presents the simultaneous quantification of 14 ECBs and related molecules in the brain, liver, and muscle, as well as white and brown adipose tissue using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The dynamic range of the method has been tuned to cover the endogenous concentrations of these analytes given the fact that they are endogenously present at different orders of magnitude. Specifically, three groups are established: 0.5-5000 ng/mL for 2-oleoyl- and 2-linoleoylglycerol and arachidonic acid, 0.05-500 ng/mL for 2-arachidonoylglycerol, and 0.0005-0.5 ng/mL for anandamide, palmitoyl-, palmitoleoyl-, stearoyl-, oleoyl-, linoleoyl-, alpha-linolenoyl-, dihomo-gamma-linolenoyl-, docosahexaenoyl-, and pentadecanoylethanolamide.