الفهرس 
Potentiometric determination of some metal ions using modified Ion selective electrodes
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Abstract
In this study, two modified selective sensors namely, screen printed electrode (SPE) and carbon paste electrode (CPE) have been developed for determination of aluminium and ferrous ions in different water and pharmaceutical samples. Two types of modifiers were used in the electrodes preparation; included methyl red and the second one used metal-methyl red complex as another effective modifier. The performance characteristics of these modified sensors have been studied according to IUPAC recommendation. For MSPEs, it was found that the best contents of methyl red were 10 and 15 mg which gave the best Nernstian slope values 20.4±0.5 and 29.1±0.2 mV decade⁻¹ over concentration range of 5.0x10⁻⁶1.0x10⁻² and 8.0x10⁻⁷1.0x10⁻² mol L⁻¹ of Al(III) and Fe(II) ions, respectively. Also, the content of the metal complex on the performance of MCPE was studied. It was found that the best content was 15 mg of Al(III) or Fe(II)-methyl red complex which gave the best Nernstian slope values 20.1±0.3 and 29.7± 0.16 mV decade⁻¹ over concentration range of 1.0x10⁻⁶1.0x10⁻² and 5.0x10⁻⁷ 1.0x10⁻ mol L-1 of Al(III) and Fe(II) ions, respectively. The modified ISEs sensors showed pH independent response for Al(III) at working pH range 3.0-5.0 and 2.5-5.0 using MSPE and MCPE, respectively, while for Fe(II) the electrodes response were pH independant at working pH range 2.0-6.0 and 1.5⁻⁷5.0 for MSPE and MCPE, respectively. Both sensors showed fast response time