LAUSR

The zwitterionic compound, levofloxacin, was determined for the first time at different pH values in pure samples, pharmaceutical preparations and spiked serum and urine samples. Different types of potentiometric sensors including poly (vinyl chloride) membrane electrode, carbon paste electrode and screen printed electrode, containing the ion pair levofloxacinium-phosphomolybdate as the electroactaive species, were used for this purpose. The effect of pH is the key factor in determining the ratio of the different species that can exist in the medium (zwitterionic, monocationic, dicationic, anionic and neutral), and so it is the controller of the electrochemical performance. The different sensors were fully characterized and optimized in terms of composition, pH effect, selectivity, response and lifetimes. The different sensors showed reliable reversibility and could be utilized for the determination of the drug in real spiked physiological fluids with reliable recovery values.