This article presents a method for the analysis of Δ9-tetrahydrocannabinol (THC), cannabinol (CBN) and cannabidiol (CBD) in breast milk.
The use of marijuana and cannabinoids has been increasing in recent years, including in childbearing women. This has resulted in cannabinoids being more frequently identified in breast milk due to its high lipid content and cannabinoids having a high lipophilicity, thereby exposing the breastfeeding infant to cannabinoids and other marijuana constituents. In the current study, THC, CBN, CBD, and their isotopically labeled standards were extracted from breast milk using a modified QuEChERS method and analyzed using ultra-performance liquid chromatography and tandem mass spectrometry. As a result of the high lipid content of breast milk, saponification of the lipids was necessary to improve overall extraction efficiency. The process efficiency percentage for THC, CBD, and CBN were 55 percent, 80 percent, and 25 percent, respectively. The recovery percentage for THC, CBD, and CBN was 95 percent, 118 percent, and 85 percent, respectively. The matrix effect percentages for THC, CBD, and CBN were 53 percent, 66 percent, and 26 percent, respectively. Linearity was assessed from 1 to 100 ng/mL for THC, CBN and CBD and had r2 > 0.996. Validation controls were prepared at 1, 3, 20, 80 and 300 ng/mL (dilution control), and the bias was determined to be less than ±20 percent with percent CVs <15 percent for all controls. Due to the limited access of genuine breast milk for routinely preparing matrix matched calibration and control materials, Enfamil® Premium™ Newborn Infant Formula (0–3 months) was evaluated as a breast milk substitute. No significant differences were observed for THC, CBN and CBD using either breast milk or formula as the matrix; thus, it was determined to be an acceptable breast milk matrix substitute. The modified QuEChERS method was determined to be a robust, reliable method for the determination of THC, CBN, and CBD in breast milk. (publisher abstract modified)