Determination of quinolones in plasma samples by capillary electrophoresis using solid-phase extraction

Area of Science:

• Analytical Chemistry
• Separation Science

Background:

• Quinolone antibiotics are widely used, necessitating reliable analytical methods for their detection.
• Accurate quantification of quinolones in biological matrices like plasma is crucial for pharmacokinetic and residue studies.

Purpose of the Study:

• To develop and validate capillary zone electrophoresis (CZE) and micellar electrokinetic capillary chromatography (MEKC) methods for separating and quantifying ten quinolone antibiotics.
• To optimize electrophoretic conditions and sample preparation for analyzing quinolones in pig plasma.

Main Methods:

• Investigated CZE and MEKC for separating ten quinolone antibiotics.
• Optimized buffer composition (40 mM sodium tetraborate, pH 8.1), organic modifier (10% methanol), and other electrolyte additives.
• Developed a C(18) solid-phase extraction method for pig plasma sample cleanup using methanol-water (70:30, v/v).

Main Results:

• Identified an optimal electrophoretic system for separating lomefloxacin, enoxacin, norfloxacin, pipemidic acid, ofloxacin, piromidic acid, flumequine, oxolinic acid, cinoxacin, and nalidixic acid.
• Achieved high mean recoveries (94.0-123.3%) for quinolones in pig plasma samples.
• Established linear calibration curves in the 5-20 mg l(-1) range with detection limits between 1.1 and 2.4 mg l(-1).

Conclusions:

• CZE and MEKC, coupled with solid-phase extraction, provide a specific, reproducible, and efficient method for quinolone antibiotic analysis in pig plasma.
• The developed method is suitable for quantitative determination of these antibiotics in biological samples.