title: Dynamic ultrasound-assisted extraction of colistin from feeds with on-line pre-column derivatization and liquid chromatography-fluorimetric detection.
abstract: A dynamic ultrasound-assisted extraction (UAE) method with on-line pre-column derivatization/high performance liquid chromatography (HPLC) and fluorimetric detection is proposed for the analysis of colistin in feed. A flow injection manifold is used for the development of the extraction and derivatization steps and for interfacing them with the separation/detection step, thus providing an on-line approach with the advantage of minimum sample handling. The derivatization was performed with ortho-phthaldialdehyde and 2-mercaptoethanol. The optimum conditions for colistin extraction and formation of the fluorescent derivative have been obtained by experimental design methodology. The use of a high-intensity probe sonication makes UAE an expeditious (7 min versus > 1 h) and efficient (93.1-98.2% versus 87.5-94% of recovery) alternative as compared with extraction using an ultrasonic bath. The within-laboratory reproducibility and repeatability, expressed as percentage of relative standard deviation, were 5.2 and 5.8, respectively.
authors.affiliation: Department of Analytical Chemistry, University of Córdoba, Marie Curie Building Annex, Campus of Rabanales, E-14071 Córdoba, Spain. a62momus@uco.es
authors.forename: S
authors.initials: S
authors.lastname: Morales-Muñoz
authors.forename: M D Luque
authors.initials: MD
authors.lastname: de Castro
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003091:Colistin / Q000032:analysis*; D017022:Flow Injection Analysis; D005456:Fluorescent Dyes; D007202:Indicators and Reagents; D012680:Sensitivity and Specificity; D014465:Ultrasonics
chemical_list: D005456:Fluorescent Dyes; D007202:Indicators and Reagents; D003091:Colistin