Potentiometric determination of diazepam, bromazepam and clonazepam using solid contact ion-selective electrodes

A. A. Salem, B. N. Barsoum, E. L. Izake

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76 Citations (Scopus)


Newly developed solid contact ion-selective electrodes (SC-ISE) have been proposed for determining diazepam, bromazepam and clonazepam 1, 4-benzodiazepines in pure forms and in pharmaceutical preparations. The electrodes are based on polyvinylchloride (PVC) membranes doped with drug-tetraphenyl borate (TPB) or drug-phosphotungestic acid (PTA) ion pair complexes as electroactive materials. The new electrodes proved highly selective with selectivity coefficients ranging from 10-4 to 10 -6 and detection limits ranging from 0.1 to 0.63μg/ml. Successful application of developed electrodes for drugs determinations in pharmaceutical preparations was obtained. Calibration graphs were linear over the ranges of 0.29-71.20, 0.79-31.62 and 0.32-31.57μg/ml for diazepam, bromazepam and clonazepam, respectively with slopes of 50-65mV per decade in the optimum pH range of 4-7. Relative average errors ≤1.72% and relative standard deviations ≤1.13% were obtained. Statistical student's t-test and F-test showed insignificant systematic error between measured and real values and also between developed ion-selective electrodes methods and a standard HPLC method.

Original languageEnglish
Pages (from-to)79-91
Number of pages13
JournalAnalytica Chimica Acta
Issue number1-2
Publication statusPublished - Nov 28 2003


  • Benzodiazepines
  • Bromazepam
  • Clonazepam
  • Diazepam
  • Ion-selective electrodes
  • PVC
  • Pharmaceutical preparations
  • Potentiometry

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Environmental Chemistry
  • Spectroscopy


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