Analysis of cannabinoids by liquid chromatography-mass spectrometry in milk, liver and hemp seed to ensure food safety

•Effective, rapid and cheap SPE and LC-MS/MS to determine cannabinoids in food.•Methanol extraction and Oasis HLB SPE clean-up provides the best recoveries.•THC in hemp seeds at concentrations lower than the maximum limit permitted in EU.•THC detected in three samples of infant feeding milk.

A method for determining cannabinoids, Δ9-tetrahidrocannabinol (THC), 11-nor-9-carboxy-Δ9-THC (THC-COOH) and 11-hidroxy-Δ9-THC (THC-OH) in milk, liver and hemp seeds based on liquid chromatography tandem mass spectrometry has been optimized and validated. Analytes were extracted with methanol and the extracts cleaned-up by solid-phase extraction using Oasis HLB (60 mg). The developed method was validated according to the Commission Decision 2002/657/EC. The decision limit (CCα) and detection capability (CCβ) ranged from 3.10-10.5 ng g−1 and 3.52-11.5 ng g−1, the recoveries were 76-118% and matrix effect ranged from −17.8% to 19.9% in the three matrices studied. The method was applied to food samples obtaining positive results for THC in hemp seeds (average 0.82 μg g−1) and three brands of junior formula milk at concentrations from 4.76 to 56.11 ng g−1. The developed method was suitable achieving identification and quantification of cannabinoids in food matrices.