Combination of magnetic solid-phase extraction with dispersive liquid–liquid microextraction followed by GC-MS for trace analysis of synthetic cannabinoids in plasma samples

Abstract

In this work, an efficient extraction method based on a combination of magnetic solid-phase extraction (MSPE) and dispersive liquid–liquid microextraction (DLLME) followed by GC-MS was developed for the determination of 5F-ADB-PINACA (ADB) and AB-FUBINACA (AB). Fe3O4 nanoparticles coated with poly ortho-aminophenol were synthesised and applied as the sorbent. Extraction parameters including pH in both the MSPE (pH 3.5) and DLLME (pH 11) steps, sorbent amount (20 mg), salt effect (10%, w/v), adsorption (20 min) and desorption time (5 min), type and volume of eluent (1.0 ml of acetone) and extraction solvent (25 µl of toluene), were optimised. Enrichment factors of 213 and 437 obtained for ADB and AB, respectively. The linear ranges of the method were obtained 0.2–50 and 0.2–50 ng ml−1 for ADB and AB, respectively. Regression coefficients above 0.998 and LODs of 0.01 and 0.005 ng ml−1 resulted. The intra- and inter-day RSDs% (n = 3) were found to be 8.3 and 7.6%, respectively. Finally, MSPE-DLLME-GC/MS was applied for the determination of analytes in plasma samples. Recoveries were within the range of 87.6–102.6 and 89.4–104% for the ADB and AB, respectively, indicating the suitability of the proposed method for analysis of ADB and AB in complicated matrices.