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

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 (60mg). The developed method was validated according to the Commission Decision 2002/657/EC. The decision limit (CCα) and detection capability (CCß) ranged from 3.10-10.5ngg-1 and 3.52-11.5ngg-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 0.82µgg-1) and three brands of junior formula milk at concentrations from 4.76 to 56.11ngg-1. The developed method was suitable achieving identification and quantification of cannabinoids in food matrices.

Estimation of alcohol consumption during "Fallas" festivity in the wastewater of Valencia city (Spain) using ethyl sulfate as a biomarker.

Alcohol consumption has been increasing in the last years and it has become a sociological problem due its derived health and safety problems. Ethyl sulfate is a secondary metabolite of the alcohol degradation that is excreted through the urine (0.010-0.016%) after alcohol ingestion and it is quite stable in water. In this study, a new methodology to determine ethyl sulfate by ion-pair liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed. Different ion-pairs and additives were tested directly in the sample extracts or in the mobile phase. The best ion-pair was set up adding 0.5M of tributylamine and 0.1% of formic acid to the sample. The limit of quantification was 0.3 µg L(-1) and the intra-day and inter-day precision of the method were ≤ 2.8 and ≤ 3.0%, respectively. Good linearity (r(2)<0.999) and low matrix effect (<30% corrected by using internal isotopically labelled internal standard) were achieved. The sampling campaign was from 4th to 20th March of 2014 covering the festivity of Fallas (15th to 19th March). Ethyl sulfate was determined in all influents of the 3 wastewater treatment plants (Pinedo I, Pinedo II and Quart-Benàger) belonging to Valencia and surrounding area. Ethyl sulfate concentrations ranged from 1.46 to 19.85 µg L(-1) and alcohol consumption ranged from 1.07 to 56.11 mL day(-1) inhab(-1), being the highest value of alcohol consumption determined during Fallas. This study presents a reliable and alternative method to traditional ones to determine alcohol consumption by population that provides real-time information of alcohol consumption.