title: Liquid-phase microextraction based on two immiscible organic solvents followed by gas chromatography with mass spectrometry as an efficient method for the preconcentration and determination of cocaine, ketamine, and lidocaine in human urine samples.
abstract: A new type of liquid-phase microextraction based on two immiscible organic solvents was optimized and validated for the quantification of lidocaine, ketamine, and cocaine in human urine samples. A hollow-fiber based microextraction technique followed by gas chromatography coupled with mass spectrometry detection was used to reduce matrix interferences and improve limits of detection. The analytes were extracted from aqueous sample with pH 11.0, into a thin layer of organic solvent (n-dodecane) sustained in the pores of a hollow fiber, and then into a second organic acceptor (acetonitrile) located inside the lumen of the hollow fiber. With the application of optimized values, good linearity was obtained in the range of 1-500 μg/L for lidocaine and ketamine and 2-500 μg/L for cocaine with the determination coefficient values (r(2) ) >0.9943. The preconcentration factors and limits of detection (S/N > 3) were 250-350 and 0.01-0.05 μg/L, respectively. Intra and interassay precision values were <7.3 and 9.3%, respectively. The method was successfully applied for the determination and quantification of target analytes in human urine samples.
authors: Department of Chemistry, Tarbiat Modares University, Tehran, Iran.
authors: Yadollah
authors: Y
authors: Yamini
authors: Shahram
authors: S
authors: Seidi
authors: Rouhollah
authors: R
authors: Feizbakhsh
authors: Tahmineh
authors: T
authors: Baheri
authors: Maryam
authors: M
authors: Rezazadeh
mesh_terms: D000777:Anesthetics / Q000302:isolation & purification / Q000652:urine*; D002849:Chromatography, Gas / Q000379:methods*; D003042:Cocaine / Q000302:isolation & purification / Q000652:urine*; D006801:Humans; D007649:Ketamine / Q000302:isolation & purification / Q000652:urine*; D008012:Lidocaine / Q000302:isolation & purification / Q000652:urine*; D059627:Liquid Phase Microextraction / Q000295:instrumentation / Q000379:methods*; D013058:Mass Spectrometry / Q000379:methods*
chemical_list: D000777:Anesthetics; D007649:Ketamine; D008012:Lidocaine; D003042:Cocaine
keywords: Cocaine; Hollow fibers; Ketamine; Lidocaine; Liquid-phase microextraction