Illicit drug powders presents a characterization challenge for the forensic chemist because the powders often have (i) an unknown and complex composition, (ii) a low concentration of active components, and (iii) a small mass. Magnetic Levitation (MagLev) uses the Magneto-Archimedes effect to separate mixtures of diamagnetic compounds into different fractions based on density while the compounds are in a vessel with a paramagnetic solution that is placed between two NdFeB permanent magnets. Most illicit drugs are hydrophilic and to avoid dissolving these powders in the MagLev we used hydrophobic solvents (i.e., mixtures of hexane and tetrachlorideethylene) with dissolved paramagnetic gadolinium (III) chelates to allow for levitation without dissolving the drugs. The MagLev enabled separation of powdered mixtures consisting of different compounds known to be used as adulterants in illicit drugs (e.g., lidocaine HCL, caffeine, dimethyl sulfone, starch, glucose, lactose, dextrose, and fructose). We fractionated mixtures consisting of up to six compounds into distinct fractions some of which consisted of only a few crystals. The relative size and position of the levitating fractions formed a characteristic ‘fingerprint’ indicating the particular drug composition and batch properties. A pipette was used to extract the fractions before further analysis with spectroscopic and chromatographic methods. MagLev is a simple, rapid, low-cost, portable, and sensitive (as small differences as ρ=4.5×10-5 g/cm3 were resolved) method that can separate and measure the density of compounds.<br/>

Density-based separation of powdered mixtures using magnetic levitation simplifies sample preparation for spectroscopic analysis and enables rapid fingerprinting of adulterants in illicit drugs

256th National Meeting (2018)

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