Selective sample pretreatment by molecularly imprinted polymer for the determination of LSD in biological fluids

For the first time, a molecularly imprinted polymer (MIP) was synthesized by a noncovalent imprinting approach for the selective extraction of an illicit drug, LSD, from hair and urine samples. For the synthesis of MIP, an analog of LSD, was taken as a dummy template, methacrylic acid as a functional monomer, and ACN as a porogen solvent. The MIP was used for offline extraction before HPLC-MS analysis. By studying the interactions taking place between the LSD and the MIP, a selective procedure was established in organic media and applied to hair samples. By this way, 0.1 ng/mg of LSD was successfully detected in hair with 82% of extraction recovery. A low retention was also obtained on the control polymer (only 9%). This procedure was then modified to obtain a selective extraction in aqueous media for the determination of LSD in urine samples. The comparison with a conventional C18 clearly demonstrated the selectivity brought by the MIP to the determination of LSD in urine. LSD was easily detected in urine at only 0.5 ng/mL with 83% of extraction recovery on the MIP and 11% on the NIP. An LOQ of 0.2 pg/mL was estimated in urine samples.