a b s t r a c tHerein, we developed a novel integrated device to perform phase separation based on ultrasound-assisted salt-induced liquid-liquid microextraction for determination of five fluoroquinones (FQs) in human body fluids. The integrated device consisted of three simple HDPE components used to separate the extraction solvent from the aqueous phase prior to retrieving the extractant. A series of extraction parameters were optimized using the response surface method based on central composite design. Optimal conditions consisted of 945 L acetone extraction solvent, pH 2.1, 4.1 min stir time, 5.9 g Na 2 SO 4 , and 4.0 min centrifugation. Under optimized conditions, the limits of detection (at S/N = 3) were 0.12-0.66 g L â1 , the linear range was 0.5-500 g L â1 and recoveries were 92.6-110.9% for the five FQs extracted from plasma and urine. The proposed method has several advantages, such as easy construction from inexpensive materials, high extraction efficiency, short extraction time, and compatibility with HPLC analysis. Thus, this method shows excellent prospects for sample pretreatment and analysis of FQs in human body fluids.© 2015 Elsevier B.V. All rights reserved.Abbreviations: PS-USLM, phase separation based on ultrasound-assisted, salt-induced, liquid-liquid microextraction; FQs, fluoroquinones; HPLC-FLD, high performance liquid chromatography equipped with fluorescence detector; PPCPs, pharmaceuticals and personal care products; HPLC, high performance liquid chromatography; MS, mass spectrometry; SPE, solid-phase extraction; LLE, liquid-liquid extraction; LPME, liquid-phase microextraction; DLLME, dispersive liquid-liquid microextraction; SALLME, salting-out assisted liquid-liquid microextraction; RSM, response surface method; CCD, central composite design; LOD, limits of detection; ER, extraction recovery; FLE, fleroxacin; OFL, ofloxacin; NOR, norfloxacin; CIP, ciprofloxacin; ENR, enrofloxacin; MgSO4, magnesium sulfate; Na2SO4, sodium sulfate; CH3COONa, sodium acetate; (NH4)2SO4, ammonium sulfate; CH3COONH4, ammonium acetate; HDPE, high-density polyethylene; LDR, linear dynamic range; RSDs, relative standard deviations; RR, relative recovery; LLE-HPLC, liquid-liquid extraction combined with high performance liquid chromatography; SPE-HPLC, solid phase extraction combined with high performance liquid chromatography; SOMC-HPLC, second-order multivariate calibration combined with high performance liquid chromatography; SSPC-HPLC, single-step precipitation cleanup method combined with high performance liquid chromatography; UFLC, ultra-fast liquid chromatography; HF-LPME-HPLC, hollow fiber-based liquid phase microextraction combined with high performance liquid chromatography.