Solid-Phase Extraction in Amphetamine and Methamphetamine Analysis of Urine

Abstract

A systematic evaluation that compares the recoveries of methamphetamine and amphetamine from spiked urine using C8, C18, strong cation exchanger (SCX), and C8-SCX mixed procedures (solid-phase extraction) is reported. Optimized experimental conditions including pH of the sample, solvent composition, and urine concentration for different solid-phase extraction sorbents were studied. The largest recoveries--greater than 86% for methamphetamine and greater than 88% for amphetamine--were achieved with a mixed adsorbent (C8-SCX) and mixed elution solvent CH2Cl2-i-propanol-NH4OH (78:20:2) at pH 6. The concentration of the urine matrix did not affect the extraction efficiency. The detection limits of methamphetamine and amphetamine in urine were obtained at 0.03 and 0.07 micrograms/mL, respectively, using gas chromatographic-mass spectrometric analysis operated in the electron impact mode.

An improved Simon reaction method to discriminate between methamphetamine and false‐positive substances

“…Therefore, a solid-phase chromogenic method using HLB cartridges, which is one of standard solid-phase extraction cartridge in forensic drug analysis, was examined to distinguish MA from Pro and HYP. Because the solid-phase of an HLB cartridge is in the reversed-phase mode, MA with an aromatic ring is expected to be strongly retained [9,13], leading to differential reaction behavior compared to Pro and HYP. MA is a basic substance, and so a 1% aqueous sodium carbonate solution was used during conditioning to keep the solid-phase basic so that MA would be more strongly retained.…”

Determination of Methamphetamine and Amphetamine in Hair by Mixed-Mode Anion Exchange Solid Phase Extraction and Liquid Chromatography–Tandem Mass Spectrometry

“…In cation-exchange cartridges, the ionic form of basic compounds, including methamphetamine and amphetamine, may bind to the sorbent followed by elution with a mixture of organic solvent and alkaline solution (Lee et al 1997;Wood et al 2005;de Castro et al 2013). However, the alkaline solution must be removed before liquid chromatographic analysis.…”

Interaction of amphetamine and its N-alkyl-substituted derivatives with micro- and mesoporous adsorbents in polar liquids

“…A higher selectivity, a lower concentration of interfering substances, a better reproducibility, and prevention of emulsion formation are among the advantages of SPE over LLE. Different sorbents packed in cartridges have been used in SPE of amphetamines but for routine determination mainly diatomaceous earth [13,14] or silica modified with mixedmode phases, e.g., strong cation-exchange and nonpolar (C-18 or C-8) groups [13,15,16], were applied. Also, modified silica with C-18 groups [17] or another functionalities (C-8, C-2, cyclohexyl, phenyl, and cyanopropyl) [18] were applied in SPE of amphetamines.…”