Determination of Fluoroquinolones in Milk Samples by Postcolumn Derivatization Liquid Chromatography with Luminescence Detection

Abstract

A liquid chromatography (LC) method with luminescence detection for the determination of eight quinolone antibiotics is reported. The system encompasses three consecutive steps: (a) chromatographic separation using reverse-phase mode (RP-LC), (b) postcolumn derivatization reaction, and (c) luminescence detection by monitoring fluorescence (FL) and time-resolved (TR) signals. The derivatization step is based on the reaction between quinolones and terbium(III) to form luminescent chelates, which were determined at lambda(ex) 340 and lambda(em) 545 nm (FL mode) or at lambda(ex) 281 and lambda(em) 545 nm (TR mode). Dynamic ranges of the calibration graphs, obtained with standard solutions of analytes and FL and TR modes, respectively, were 190-3500 and 316-2000 ng mL-1 for marbofloxacin, 8-3500 and 8.1-1500 ng mL-1 for ciprofloxacin, 6.2-3500 and 13-1500 ng mL-1 for danofloxacin, 7.4-3500 and 8.4-1500 ng mL-1 for enrofloxacin, 14-3500 and 20-2000 ng mL-1 for sarafloxacin, 12.5-3500 and 13.9-1200 ng mL-1 for difloxacin, 7.6-3500 and 13-3000 ng mL-1 for oxolinic acid, and 9-2000 and 130-3000 ng mL-1 for flumequine. Limit of detection values obtained using FL and TR modes, respectively, were 60 and 95 ng mL-1 for marbofloxacin, 2 and 2.4 ng mL-1 for ciprofloxacin, 1.9 and 3.9 ng mL-1 for danofloxacin, 2.2 and 2.5 ng mL-1 for enrofloxacin, 3.8 and 7 ng mL-1 for sarafloxacin, 4 and 4.2 ng mL-1 for difloxacin, 2.3 and 4 ng mL-1 for oxolinic acid, and 2.7 and 40 ng mL-1 for flumequine. The precision was established at two concentration levels of each analyte and expressed as the percentage of relative standard deviation with values ranging between 1.9 and 7.8%. The validation procedure for the analysis of samples was carried out using European Community recommendations, and the decision limit and detection capability were calculated for bovine whole milk. The method was applied to whole, semiskimmed, and skimmed milk samples spiked with the target analytes, and the recoveries ranged between 93.3 and 106.0%.

Multiclass analysis of 23 veterinary drugs in milk by ultraperformance liquid chromatography–electrospray tandem mass spectrometry

“…Many papers have been published in past years on the different classes of veterinary drugs, such as bioassay techniques [6,7] and liquid chromatography (LC) with UV or photodiode array detection [8][9][10]. However, these methods are less sensitive for determining drug residues compared to mass spectrometry (MS).…”

Luminescent Chemical and Physical Sensors Based on Lanthanide Complexes

“…The plurality of these interactions indicates the problems of sensors including lanthanide complexes as receptors for the specific recognition of a certain analyte. The same is the case for free lanthanide ions that have been presented for the luminescent determination of pharmaceutically active compounds such as antibiotics [15][16][17]. Nevertheless, Molina-Diaz et al have Scheme 6 Europium complex as monomer for the preparation of humidity sensitive luminescent copolymers described a sensor for flow-injection analysis (FIA) that can be applied to the determination of p-aminobenzoic acid in pharmaceutical preparations [113].…”

“…Furthermore, this overview does not cover lanthanide systems in which the analyte itself actuates as sensitizer for the lanthanide ion. This principle can be used for the determination of antibiotics in aqueous solution [15][16][17].…”

Determination of fluoroquinolone antibiotics by microchip capillary electrophoresis along with time-resolved sensitized luminescence of their terbium(III) complexes

“…A method for the determination of two FQs based on the TSL plasmonically enhanced by silver nanoparticles has also been reported [25]. In addition, terbium(III) has been used as postcolumn derivatizing reagent in liquid chromatography for the determination of several FQs in milk samples [26]. However, although capillary electrophoresis (CE) has been also used for FQs determination [27], to the best of our knowledge, TSL has not been described as a detection system for this purpose.…”