Determination of Cannabinoids in Breast Milk Using QuEChERS and Ultra-Performance Liquid Chromatography and Tandem Mass Spectrometry.

Use of marijuana and cannabinoids has been on the rise in recent years, including in childbearing women. This has resulted in cannabinoids being more frequently identified in breast milk as a result of its high lipid content and cannabinoids having a high lipophilicity, thereby exposing the breastfeeding infant to cannabinoids and other marijuana constituents. Presented is a method for the analysis of Δ9-tetrahydrocannabinol (THC), cannabinol (CBN) and cannabidiol (CBD) in breast milk. 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 are 55%, 80% and 25%, respectively. The recovery percentage for THC, CBD and CBN are 95%, 118% and 85%, respectively. The matrix effect percentage for THC, CBD and CBN are 53%, 66% and 26%, 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% with %CVs <15% 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.