title: Surfactant-assisted dispersive liquid-liquid microextraction of nitrazepam and lorazepam from plasma and urine samples followed by high-performance liquid chromatography with UV analysis.
abstract: Surfactant-assisted liquid-liquid microextraction followed by high-performance liquid chromatography with UV detection has been developed for the simultaneous preconcentration and determination of lorazepam and nitrazepam in biological fluids. In this study, an ionic surfactant (cetyltrimethyl ammonium bromide) was used as an emulsifier. The predominant parameters affecting extraction efficiency such as the type and volume of extraction solvent, the type and concentration of surfactant, sample pH, and the concentration of salt added to the sample were investigated and opted. Under the optimum conditions (extraction solvent and its volume, 1-octanol, 70 μL; surfactant and its concentration, 1 mL of ultra-pure water containing 2 mmol L-1cetyltrimethyl ammonium bromide; sample pH = 9 and salt content of 10% NaCl w/v), the preconcentration factors were obtained in the range of 202-241 and 246-265 for nitrazepam and lorazepam, respectively. The limits of quantification for both drugs were 5 μg L-1in water sample and 10 μg L-1in biological fluids with R2values higher than 0.993. The suitability of the proposed method was successfully confirmed by the extraction and determination of the target drugs in human urine and plasma samples in the range of microgram per liter.
authors.affiliation: Faculty of Chemistry, Shahid Beheshti University, G.C, Evin, Tehran, Iran.
authors.forename: Karam
authors.initials: K
authors.lastname: Molaei
authors.affiliation: Faculty of Chemistry, Shahid Beheshti University, G.C, Evin, Tehran, Iran.
authors.forename: Ali Akbar
authors.initials: AA
authors.lastname: Asgharinezhad
authors.affiliation: Faculty of Chemistry, Shahid Beheshti University, G.C, Evin, Tehran, Iran.
authors.forename: Homeira
authors.initials: H
authors.lastname: Ebrahimzadeh
authors.affiliation: Faculty of Chemistry, Shahid Beheshti University, G.C, Evin, Tehran, Iran.
authors.forename: Nafiseh
authors.initials: N
authors.lastname: Shekari
authors.affiliation: Faculty of Chemistry, Shahid Beheshti University, G.C, Evin, Tehran, Iran.
authors.forename: Niloofar
authors.initials: N
authors.lastname: Jalilian
authors.affiliation: Faculty of Chemistry, Shahid Beheshti University, G.C, Evin, Tehran, Iran.
authors.forename: Zhara
authors.initials: Z
authors.lastname: Dehghani
keywords: Biological fluids; Liquid-liquid microextraction; Lorazepam; Nitrazepam; Surfactants