Determination of difloxacin and sarafloxacin in chicken muscle using solid-phase extraction and capillary electrophoresis.
ABSTRACT This paper describes a method for residue analysis of difloxacin and sarafloxacin in chicken muscle. Clean-up and preconcentration of the samples are effected by solid-phase extraction (C18) and the determination is carried out by capillary electrophoresis using a photodiode array detection system. The method was validated with satisfying results. The calibration graphs are linear for difloxacin and sarafloxacin from 50 to 300 microg/kg. The limit of detection obtained for difloxacin and sarafloxacin are 10 and 25 microg/kg, respectively, which allows the detection of positive muscle samples at the required maximum residue limits of European Union.
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ABSTRACT: A magnetic solid-phase extraction (MSPE) method combined with capillary electrophoresis for the simultaneous determination of seven quinolones (QNs) (danofloxacin, ciprofloxacin, marbofloxacin, enrofloxacin, difloxacin, oxolinic acid, and flumequine), using (S)-(+)-6-methoxy-α-methyl-2-naphthaleneacetic acid as internal standard, in milk samples was developed. The variables involved in the preconcentration magnetic procedure were: the composition of the magnetic support composition, the sample pH, and the weight of magnetic adsorbent used. The variables were optimized using a simplex-lattice design. Different magnetite covered with octyl-phenyl silica adsorbents were synthesized by varying the molar ratio of phenyltrimethylsilane and octyltrimethoxysilane; the solids were evaluated for QN preconcentration. Under optimal conditions, a linear range was obtained from 27 to 1000 μg L(-1) with limits of detection ranging from 9 to 12 μg L(-1) for the seven QNs. The absolute recoveries of the seven QNs at three different spiked levels (40, 150, and 400 μg L(-1) ) ranged from 74% to 98% with a relative standard deviation less than 10% in all cases. The proposed method was applied to analyze 20 whole milk samples of different brands. All samples were positive for the presence of QN residues; in some cases, extract dilution was required. The concentrations found are in the range from 31.1 to 5047.3 μg L(-1) . Marbofloxacin was the most frequently found. The method proposed offers advantages in terms of simplicity, sensitivity, efficiency, cost, and analysis time making it an alternative for the analysis of QNs in whole milk samples.Electrophoresis 07/2012; 33(13):2041-8. · 3.26 Impact Factor
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ABSTRACT: In this study, a method for the detection of sarafloxacin in pig and chicken muscles was developed using HPLC-FLD as a regulatory residue technique. Good extraction efficiency was achieved using a mixture of 1% orthophosphoric acid-0.2 m MgCl(2) in water and acetonitrile as an extraction solvent, and n-hexane partitioning and centrifugation for cleanup was used in the absence of dehydration. Specificity, linearity, detection and quantification limits, recovery, accuracy and precision were all validated, and all results were sufficient for the SARA regulatory residue method in pig and chicken muscles. The method developed and described herein was not only simple but also reliable, and was applied to market samples to determine their residue contents.Biomedical Chromatography 03/2011; 25(3):405-11. · 1.95 Impact Factor
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ABSTRACT: A sensitive capillary electrophoresis-laser-induced fluorescence method has been developed for the determination of six fluoroquinolones of human (ofloxacin, lomefloxacin, and norfloxacin) and veterinary use (danofloxacin, enrofloxacin, and sarafloxacin) in different kinds of water. Fluorescence detection was achieved using a He-Cd laser, with a wavelength of 325 nm. Separation was performed in a fused-silica capillary, and conditions were optimized to obtain the most adequate separation and with the best sensitivity. The separation was carried out in a 70-cm-long capillary (75 microm internal diameter, effective length 55 cm) by using a 125 mM phosphoric acid separation buffer at pH 2.8, with 36% of methanol. The water sample pretreatment involved the separation and preconcentration of the analytes by solid phase extraction. Two reverse-phase cartridges have been evaluated, namely Oasis hydrophilic-liphophilic balance and Strata-X; the latter provided the best recoveries for the selected analytes. The method shows very low detection limits (0.3-1.9 ng/L) with acceptable recoveries and precisions and has been successfully applied to the analysis of well and tap water samples.Analytical and Bioanalytical Chemistry 02/2010; 396(4):1551-7. · 3.66 Impact Factor