Sensitive Quantification of Cannabinoids in Milk by Alkaline Saponification–Solid Phase Extraction Combined with Isotope Dilution UPLC–MS/MS

Abstract Maternal exposure to marijuana during the lactation period—either active or passive—has prompted concerns about transmission of cannabinoids to breastfed infants and possible subsequent adverse health consequences. Assessing these health risks requires a sensitive analytical approach that is able to quantitatively measure trace-level cannabinoids in breast milk. Here, we describe a saponification–solid phase extraction approach combined with ultra-high-pressure liquid chromatography–tandem mass spectrometry for simultaneously quantifying Δ9-tetrahydrocannabinol (THC), cannabidiol (CBD), and cannabinol (CBN) in breast milk. We demonstrate for the first