title: Liquid-liquid-liquid microextraction followed by HPLC with UV detection for quantitation of ephedrine in urine.
abstract: Liquid-liquid-liquid microextraction (LLLME) in combination with HPLC and UV detection has been used as a sensitive method for the determination of ephedrine in urine samples. Extraction process was performed in a homemade total glass vial without using a Teflon ring, usually employed. Ephedrine was first extracted from 3.5 mL of urine sample (pH 12) into a microfilm of toluene/benzene (50:50). The analyte was subsequently back extracted into an acidic microdrop solution (pH 2) suspended in the organic phase. The extract was then injected into the HPLC system directly. An enrichment factor of 137 along with a good sample clean-up was obtained under the optimized conditions. The calibration curve showed linearity in the range of 0.01-50 mg/L with regression coefficient corresponding to 0.998. The LODs and LOQs, based on a S/N of 3 and 10, were 5 and 10 microg/L, respectively. The method was eventually applied for the determination of ephedrine in urine sample after oral administration of 5 mg single dose of drug.
authors.affiliation: Department of Chemistry, Sharif University of Technology, Tehran, Iran. bagheri@sharif.edu
authors.forename: Habib
authors.initials: H
authors.lastname: Bagheri
authors.forename: Faezeh
authors.initials: F
authors.lastname: Khalilian
authors.forename: Laleh Enayati
authors.initials: LE
authors.lastname: Ahangar
mesh_terms: D005591:Chemical Fractionation / Q000295:instrumentation / Q000379:methods*; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods*; D004300:Doping in Sports; D004809:Ephedrine / Q000737:chemistry / Q000652:urine*; D006801:Humans; D015394:Molecular Structure; D015203:Reproducibility of Results; D012997:Solvents / Q000737:chemistry; D013566:Sympathomimetics / Q000737:chemistry / Q000652:urine*
chemical_list: D012997:Solvents; D013566:Sympathomimetics; D004809:Ephedrine