Ion-Selective Membrane Sensors for the Determination of Ciprofloxacin Hydrochloride in Water and Pharmaceutical Formulation

The construction and electrochemical response characteristics of six Ciprofloxacin-selective electrodes were investigated using precipitation based technique with sodium tetraphenyl borate (TPB), phosphomolybdate (PMA) and phosphotungstate (PTA); respectively upon using polyvinyl chloride (PVC) matrix and dibutyl phthalate (DBP) as a plasticizer. The resultant sensors have different forms, either as membrane electrodes (sensors 1, 3 and 5) or as coated wire electrodes (sensors 2, 4 and 6). Linear responses of CIP within the concentration ranges of 10−6 to 10−2 mol/L for sensors 1, 2 and 5 while for sensors 3 and 4, the linear responses were within the concentration ranges of 10−5 to 10−2 mol/L and for sensor 6 it shows linear responses within the concentration ranges of 10−7 to 10−2 mol/L. Nernstian slopes of 51.7, 50.7, 58.3, 57.7, 44 and 41.8 mV/decade were observed over the pH range of (5–9) for sensors 1, 2, 5 and 6 and over range of (5-7) for sensor 3 and 4 respectively. The selectivity coefficients of the developed sensors indicated excellent selectivity for CIP. The proposed sensors displayed useful analytical characteristics for the determination of CIP in water samples and pharmaceutical preparation.