title: Combined application of dispersive liquid-liquid microextraction based on the solidification of floating organic droplets and charged aerosol detection for the simple and sensitive quantification of macrolide antibiotics in human urine.
abstract: A novel analytical method combining dispersive liquid-liquid microextraction based on the solidification of floating organic droplets (DLLME-SFO) and liquid chromatography with charged aerosol detection (LC-CAD) was established. For the first time, CAD was applied for the detection of macrolide antibiotics lacking chromophores. Parameters influencing the microextraction efficiency were systematically investigated, and the optimized microextraction conditions yielded high enrichment factors in the range of 60-106. The combined application of DLLME-SFO and LC-CAD provided the sensitivity of the method, expressed as the limit of detection (LOD), as low as 10 to 40ngmL(-1) and intra-day and inter-day precisions below 8.7% and 12.6%, respectively. The measured absolute recovery values were approximately 100%, indicating that the extraction efficiency was very high. Direct comparisons of the liquid-liquid extraction and organic solvent precipitation methods demonstrated that the proposed method was more sensitive, specific, rapid, and environmentally friendly for the determination of five macrolide antibiotics in human urine. The results suggest that the combined use of DLLME-SFO and LC-CAD may be applicable to the analysis of various compounds with poor to no chromophores in complex matrices.
authors.affiliation: College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 151-742, Republic of Korea; Department of Biomedical Sciences, College of Medicine, Inha University, Incheon 400-712, Republic of Korea.
authors.forename: Shaodong
authors.initials: S
authors.lastname: Jia
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: So-Ra
authors.initials: SR
authors.lastname: Park
authors.forename: Yeonsuk
authors.initials: Y
authors.lastname: Ryu
authors.forename: Il Ho
authors.initials: IH
authors.lastname: Park
authors.forename: Jeong Hill
authors.initials: JH
authors.lastname: Park
authors.forename: Soon-Sun
authors.initials: SS
authors.lastname: Hong
authors.forename: Sung Won
authors.initials: SW
authors.lastname: Kwon
authors.forename: Jeongmi
authors.initials: J
authors.lastname: Lee
mesh_terms: D000336:Aerosols / Q000032:analysis*; D000900:Anti-Bacterial Agents / Q000032:analysis / Q000652:urine*; D006801:Humans; D059627:Liquid Phase Microextraction / Q000379:methods* / Q000592:standards; D018942:Macrolides / Q000032:analysis / Q000652:urine*
chemical_list: D000336:Aerosols; D000900:Anti-Bacterial Agents; D018942:Macrolides
keywords: Charged aerosol detection; Dispersive liquid–liquid microextraction; Macrolide antibiotics; Solidification of organic droplets; Urine sample