Determination of Ofloxacin in Pharmaceuticals, Human Urine and Serum Using a Potentiometric Sensor

An ofloxacin‐selective electrode was developed for application in pharmaceutical preparations, serum and urine analysis. The electrode is based on tetrakis[3,5‐bis(trifluoromethyl)phenyl]borate as ion exchanger in a poly(vinyl chloride) membrane. The sensor displayed a Nernstian response for ofloxacin over a wide concentration range (3×10 −6 –1×10 −2  mol L −1 ) with a slope of 55±1 mV per decade of concentration and a practical detection limit of 1×10 −6  mol L −1 . The electrode was successfully applied to the determination of ofloxacin in samples with no pretreatment steps, adequate accuracy and precision and recoveries within the intervals of 94–107 %.