RESUMO
Liquid-phase microextraction is a novel pretreatment technique for biological samples developed on the basis of liquid-phase extraction technology, which is simple, rapid, economical, and environmentally friendly, and has been widely used in the analysis of biological matrix samples such as blood, urine, and saliva. In this paper, we review the basic principles of the main modes of liquid-phase microextraction techniques, i.e., single-drop microextraction, dispersive liquid-liquid microextraction, and hollow-fiber liquid-phase microextraction, and the progress of their applications in biological sample pretreatment by reviewing the literature in the past five years, with a view to providing technical support and reference for sample pretreatment in the fields of in vivo drug analysis, pharmacokinetic studies and new drug development.
RESUMO
A method for the determination of caffeine in urea was developed based on bubble-in-drop single drop microextraction (BID-SDME) followed by gas chromatography/mass spectrometry (GC-MS).Under the optimum conditions including chloroform as extraction solvent, an exposure volume of 1 μL, a bubble volume of 1.6 μL, stirring for 5 min at 300 r/min, 15% (m/V) NaCl, and a distance of 1 cm between bubble and stirring bar, the detection limit of this method was as low as 0.003 mg/L and the linear range was from 0.005 mg/L to 10 mg/L with correlation coefficient of 0.982.The recoveries of caffeine were from 89.2% to 107.5% at different spiked levels in human urine and the relative standard deviation (RSD, n=6) was less than 8%.