Dispersive liquid–liquid microextraction of quinolones in porcine blood: Optimization of extraction procedure and CE separation using experimental design

Abstract

A dispersive liquid-liquid microextraction procedure was developed to extract nine fluoroquinolones in porcine blood, six of which were quantified using a univariate calibration method. Extraction parameters including type and volume of extraction and dispersive solvent and pH, were optimized using a full factorial and a central composite designs. The optimum extraction parameters were a mixture of 250 μL dichloromethane (extract solvent) and 1250 μL ACN (dispersive solvent) in 500 μL of porcine blood reached to pH 6.80. After shaking and centrifugation, the upper phase was transferred in a glass tube and evaporated under N steam. The residue was resuspended into 50 μL of water-ACN (70:30, v/v) and determined by CE method with DAD, under optimum separation conditions. Consequently, a tenfold enrichment factor can potentially be reached with the pretreatment, taking into account the relationship between initial sample volume and final extract volume. Optimum separation conditions were as follows: BGE solution containing equal amounts of sodium borate (Na B O ) and di-sodium hydrogen phosphate (Na HPO ) with a final concentration of 23 mmol/L containing 0.2% of poly (diallyldimethylammonium chloride) and adjusted to pH 7.80. Separation was performed applying a negative potential of 25 kV, the cartridge was maintained at 25.0°C and the electropherograms were recorded at 275 nm during 4 min. The hydrodynamic injection was performed in the cathode by applying a pressure of 50 mbar for 10 s.

Dispersive liquid–liquid microextraction of quinolones in porcine blood: Validation of a CE method using univariate calibration or multivariate curve resolution‐alternating least squares for overlapped peaks

“…In our previous work , we optimized the separation of nine FQs and the IS using the response surface methodology by applying experimental designs. The results of this study were optimized conditions that assure the complete analyte separation in the shortest analysis time when a standard solution of target analytes was analyzed.…”

“…Sample preparation was carried out following the method proposed in our previous work . Figure A shows the sequence of sample clean‐up and extraction of FQs from porcine blood samples.…”

“…In the first part of this work , we showed that there are numerous studies and reviews about the determination of FQs in animal tissues, eggs, and bovine milk; however, the number of studies specifically addressing FQs in porcine plasma or serum remains quite small. Hence, we developed an analytical method by CE to determine flumenique (FLU), difloxacin (DIF), enrofloxacin (ENF), marbofloxacin (MRF), ofloxacin (OFL), ciprofloxacin (CPF), enoxacin (ENO), danofloxacin (DNF), and gatifloxacin (GTF) in samples of porcine blood.…”

Analysis of antibiotics by CE and CEC and their use as chiral selectors: An update

“…Neither antibiotics nor metabolites were found when the MEKC method was applied to real samples. The determination of fluoroquinolones was also carried out in other matrices such as milk and porcine blood . MSPE with montmorillonite magnetic molecularly imprinted polymers (MMMIPs) as adsorbents and CZE were employed for the selective extraction and determination of fleroxacin, gatifloxacin, lomefloxacin and norfloxacin .…”

“…With MSPE‐CZE, the LODs obtained were below 18.8 μg/mL and the recoveries achieved were between 97.2 and 108.6%. The research group of Vera‐Candioti developed an interesting dispersive liquid‐liquid microextraction (DLLME)‐CZE‐UV method for the determination of nine fluoroquinolones in porcine blood samples . A full factorial design was employed to identify the conditions that affected the extraction efficiency by DLLME whereas a central composite design was used to determine the best combination of the extraction conditions that ensured the optimum efficiency.…”