Modified carbon paste versus graphite coated ion selective electrodes for the determination of amantadine and moroxydine hydrochlorides in pharmaceutical and urine samples

Newly developed electrochemical sensors based on modified carbon paste and graphite coated ion selective electrodes (ISEs) were proposed for determining amantadine and moroxydine hydrochlorides' nonnucleoside antiviral drugs. The new electrodes have proven sensitive with detection limits of 0.19-2.08 μg/ml. Linear calibration graphs in the ranges of 10^-1 - 10^-5 M were obtained. The optimum pH range recorded for all developed electrodes was 4-8. Relative average error ≤ 4% was obtained in pure samples with standard deviations ≤ 3. The developed sensors were successfully applied in the determination of the target drugs in pharmaceutical and human's urine samples. Statistical student-t test has been applied and satisfactory results were obtained. The effects of membranes and carbon paste's compositions, homogeneities, pinholes formation and different types of plasticizers on electrodes performances were evaluated, as well as the difference between carbon paste and graphite coated sensor electrodes.