An-Najah National University

An-Najah Blogs


  • Thursday, January 1, 2004
  • Enhancement of n-GaAs characteristics by combined heating, cooling rate and metalloporphyrin modification techniques
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  • Different modification techniques, namely, preheating, controlling the cooling rate and modification with tetra(-4-pyridyl)porphyrinatomanganese(III) have been used to enhance photoelectrochemical characteristics of n-GaAs electrodes in light-to-electricity conversions. Combination of such three techniques together yielded electrodes with better darkcurrent density vs potential plots and photocurrent density vs potential plots. Higher efficiency and stability were also observed for electrodes modified by such combined techniques.
    Solid State Sciences, Volume 6, Issue 1, January 2004, Pages 139-146

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  • Monday, January 1, 2001
  • Determination of Aminophylline by Cathodic Stripping Voltammetry
  • Published at:Not Found
  • Aminophylline is determined by cathodic stripping voltammetry (CSV) in BR buffer, pH 7.5 at a hanging mercury drop electrode. The detection limit was 3x10-8 M after 60 s accumulation at -0.60 V versus Ag/AgCl reference electrode. The linear range demonstrated up to 5x10-7 M using CSV. The interference caused by some purine derivatives, anions and some metal cations on the peak current was studied. The peak current is enhanced by theophylline, some methylguanines and copper (II) while it decreased or disappeared by citrate, chloride and Triton X-100 surfactant. The method has good sensitivity and its application to pharmaceutical samples is possible. Keywords: Determination of aminophylline, stripping voltammetry, cathodic stripping voltammetry, adsorptive voltammetry, dosage forms.
    An-Najah University Journal for Research - Natural Sciences (A) ISSN: 1727-2114
    Volume 15 , 2001, Pages: 021-028
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  • Saturday, January 1, 2000
  • Voltammetric and spectrophotometric determination of nizatidine in pharmaceutical formulations
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  • Two methods are described for quantitative determination of nizatidine. The first is a cathodic stripping voltammetric method which is based on the accumulation of the compound at the hanging mercury drop electrode. The adsorptive stripping response was evaluated with respect of accumulation time, potential, concentration, pH and other variables. A linear calibration graph was obtained over the range 3.0 × 10-8 - 1.0 × 10-6 M with a detection limit 3.0 × 10-8 M after a 20s accumulation time at -0.2 V accumulation potential. On the other hand, it was found that the detection limit could be lowered to 1.0 x 10 8 M after 180s accumulation time at -0.2 V accumulation potential. The relative standard deviation was in the range 1.2-2.0% for six measurements. The tolerance amounts of the common excipients have also been reported. The second is a spectrophotometric method which is based on the formation and extraction of the ion-pair complex formed between nizatidine and either bromocresol green or
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  • Wednesday, December 1, 1999
  • Electrochemical study on the determination of tinidazole in tablets
  • Published at:Not Found
  • The electrochemical reduction of tinidazole has been carried out in aqueous solution in the pH range 1.8–11.3 by differential-pulse (DP) polarography. Tinidazole exhibits one or two reduction peaks depending on pH. In strongly acidic solution (pH<4.5), one reduction peak was obtained and it was suitable for analytical purposes. A method for the determination of tinidazole by DP polarography in Britton–Robinson buffer of pH 3.0, which allows quantification over the range 0.03–7.30 μg/ml, was proposed. The method was successfully applied to the determination of tinidazole in tablets with mean recovery and relative standard deviation of 98.7 and 3%, respectively. Excipients did not interfere in the determination.
    Journal of Pharmaceutical and Biomedical Analysis, Volume 21, Issue 4, December 1999, Pages 881-886
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Raqi Moh'd Shubitah
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