Application of single drop liquid-liquid-liquid microextraction for the determination of fluoroquinolones in human urine by capillary electrophoresis.

A simple and novel method of single drop liquid-liquid-liquid microextraction (SD-LLLME) coupled with capillary electrophoresis (CE) for the determination of six fluoroquinolones (FQs) was developed. The method was eventually applied to extraction and preconcentration of FQs in human urine samples. Good linear relationships were obtained for all analytes in a range of 40-1000 μg L⁻¹ with the correlation coefficients from 0.9913 to 0.9995. The limit of detections (LODs) varied from 7.4 to 31.5 μg L⁻¹ at a signal-to-noise (S/N) of 3. The recoveries at two spiking levels were 81.8-104.9% with relative standard deviations <8.3%.