US EPA

3230550 

Journal Article 

Surfactant-assisted dispersive liquid-liquid microextraction of nitrazepam and lorazepam from plasma and urine samples followed by high-performance liquid chromatography with UV analysis 

Molaei, K; Asgharinezhad, AliA; Ebrahimzadeh, H; Shekari, N; Jalilian, N; Dehghani, Z 

2015 

Yes 

Journal of Separation Science
ISSN: 1615-9306
EISSN: 1615-9314 

38 

22 

3905-3913 

10.1002/jssc.201500586 

WOS:000365320800013 

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 mu L; surfactant and its concentration, 1 mL of ultra-pure
water containing 2 mmol L-1 cetyltrimethyl 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 mu g
L-1 in water sample and 10 mu g L-1 in biological fluids with R-2 values 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. 

Biological fluids; Liquid-liquid microextraction; Lorazepam; Nitrazepam; Surfactants