New electrode based on ofloxacin-methyl orange as ion-pair for determination of ofloxacin in pharmaceutical preparations, urine and blood

Abstract

A basic, rapid, and straightforward potentiometric method was developed for the determination of ofloxacin in pharmaceutical preparations and human fluids. Three PVC membranes for ofloxacin (OFN) were prepared by combining the ion-pair compound ofloxacin-methyl orange (OFN-MO) with three different plasticizers: Tris (2-Ethylhexyl) phosphate (TEHP), Di-butyl phthalate (DBPH), and Di-butyl sebacate (DBS). These electrodes generated Nernstain responses of 58.58, 51.54, and 57.08mV/decade with linear ranges of (5*10−5 – 1*10−2 )M for membranes containing TEHP, DBPH, or DBS as plasticizers. The detection limits were equivalent to 4.6*10−6, 3.8*10−5, and 4.8*10−5 M, respectively. pH ranges were also investigated at various concentrations for ofloxacin solutions, lifetime and selectivity. The potentiometric methods such as direct addition, standard addition, and multiple standard additions were applied for the determination of ofloxacin. The proposed TEHP electrode was successfully used to determine the ofloxacin in a variety of pharmaceutical formulations and human fluids.