Development of a new pH assisted homogeneous liquid-liquid microextraction by a solvent with switchable hydrophilicity: Application for GC-MS determination of methamphetamine.

In this study, a new method based on homogeneous liquid-phase microextraction was developed for the determination of methamphetamine (MA) in urine samples. Dipropylamine (DPA), as a solvent with switchable hydrophilicity, was used as the extraction solvent and can be miscible/immiscible based on variable pH values of the aqueous sample solution. The effects of operational extraction parameters such as DPA volume, temperature, the amount of added acid and base solutions, and NaCl content of the sample were investigated. Under optimal conditions the preconcentration factor, limit of detection and linearity of the method were achieved in the ranges of 98.8, 1.5 µgL-1 and 5-1500 µgL-1, respectively. Also, within-run precision, between-run precision and robustness of the method were investigated. Finally, the proposed method was successfully applied to the analysis of MA in urine sample.