RESUMEN
An original, selective and automated method, for the microextraction by packed sorbent (MEPS) of Δ9-tetrahydrocannabinol (THC), 11-hydroxy-Δ9-tetrahydrocannabinol (THC-OH), and 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) from human urine, was developed by using (i) a catechin-molded molecularly imprinted polymer (MIP), (ii) a new lab-made MEPS device easily repackable with any commercial or lab-made sorbent, and (iii) a lab-made multi syringe autosampler. Analyses were performed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and the developed method proved to be precise, accurate and showed good linearity. Determination coefficients ranged from 0.96 to 0.99, in the range of 5-250 ng mL-1. Limits of detection and quantification ranged between 1.0 and 5.0 ng mL-1 and 5.0 and 20.0 ng mL-1. The method was successfully applied in the analysis of real urine samples. The same packed syringe was effectively used over 90 consecutive extractions without carry-over effects.