A LC-MS/MS method for the determination of common synthetic cathinones in meconium.

New psychoactive substances have been introduced into the market in the last years due to their unregulated status. Synthetic cathinones are one of their main representatives, and they have shown to produce neonatal complications. It is important to have objective tools to identify in utero exposure to drugs that have shown to produce neonatal complications. An analytical method was developed and fully validated for the determination of common synthetic cathinones, including methylone, methedrone, mephedrone, 3,4-methylenedioxypyrovalerone (MDPV), (±)-4-fluoromethamphetamine and 4-fluoromethcathinone in meconium. Meconium (0.25 ± 0.02 g) was homogenized with methanol by sonication for 30 min. After centrifugation, the sample was extracted with Oasis MCX columns. The analysis was performed by LC-MS/MS using an Atlantis T3 column (3 μm, 2.1 × 50 mm) and a gradient with acetonitrile and 0.1% formic acid in water. Method validation included the following parameters: selectivity (no endogenous or exogenous interferences), limits of detection (n = 3, 0.5-1 ng/g) and quantification (n = 3, 1-2 ng/g), linearity (n = 5, LOQ-200 ng/g), imprecision (n = 15, 0% to 10%), accuracy (n = 15, 87.3% to 97.8%), matrix effect (n = 10, -76% to -28.1%), extraction efficiency (n = 6, 63.7% to 91.3%), total process efficiency (n = 6, 16% to 60.2%) and stability for 72 h in the autosampler (n = 3, %loss = -6.7% to 5.1%). The method was applied to 28 meconium specimens.