Determination of N-methyl-1-phenol-2-propanamine trace amounts in urine samples with molecular-imprinted polymer based sorbents

N-methyl-1-phenyl-2-propanamine is one of the compounds controlled in the clinic and forensic toxicology, and its determination methods with the high sensitivity could significantly improve the confidence of analyses. Taking into account that the equipment of the most Russian laboratories of forensic and clinical toxicology is generally based on the GC/MS systems, the sensitivity improvement for the methods could be achieved by the selective extraction of analytes during the sample preparation. The solid-phase extraction (SPE) using molecular imprinted polymer (MIP) - based sorbents is one of the new techniques of the selective extraction of analytes. In this study, two types of MIP-based cartridges (SupelMIP SPE – Amphetamines and SupelMIP SPE – Full Beta-Receptors) and conventional cation-mixed-based cartridges (Isolute Confirm HCX) were used for N-methyl-1-phenyl-2-propanamine determination in urine. The eluates were dried under the steam of nitrogen, followed by the derivatization with trifluoracetyl anhydride. Analyses were performed by GC/MS with electron ionization in scan mode. The achieved average recovery of N-methyl-1-phenyl-2-propanamine was 65% for «SupelMIP SPE – Amphetamines» cartridges, 78% for «SupelMIP SPE – Full Beta-Receptors» cartridges and 68% for «Isolute Confirm HCX» cartridges. Although comparable in recoveries, the limit of detection (LOD) of the analyte in urine prepared with cation-mixed-based cartridges was 10 ng∙ml -1 , while for MIP-based cartridges the achieved LOD was 1 ng∙ml -1 . The significant difference in sensitivity was due to the influence of the matrix compounds. The main part of the peaks in chromatograms of the samples prepared with MIP-based sorbents were associated with impurities of reagents, solutions, sorbents or soiled dishes, but not with urine content. In comparison with cation-exchange sorbents, the use of MIP-based sorbents allowed to increase the sensitivity by an order of magnitude in conducting confirmatory GC-MS analysis for N-methyl-1-phenyl-2-propanamine determination. Key words : gas chromatography, mass spectrometry, identification, molecular-imprinted phase sorbents, solid-phase extraction, N-methyl-1-phenyl-2-propanamine (Russian) DOI: http://dx.doi.org/10.15826/analitika.2017.21.1.002 V . N . Bykov 1 , A . S . Nikiforov 1 , V . M . Goncharov 2 , V . V . Vasin 2 , A . M . Sventitsckaya 2 1 Research and Testing Institute of Military medicine of the Ministry of Defense of the Russian Federation», ul. Lesoparkovaya, 4, St. Petersburg, 195043, Russian Federation 2” Limited Liability Company «Innovation Pharmaceutical company «Silver-Pharm», Industrial’nyi pr., 45, St. Petersburg, 195279, Russian Federation