A potentiometric sensor based on heterogeneous inorganic chelating ion exchanger for the determination of AIIII ions

Department of Chemistry, Zakir Husain College (University of Delhi), J. L. Nehru Marg, New Delhi-11 0 002, India

E-mail: himan_007@rediffmail.com

Manuscript received 13 August 2004, revised 2 March 2005, accepted 3 March 2005

Preparation and applications of a novel long life aluminium ion membrane electrode sensor based on heterogeneous inorganic chelating ion exchanger i.e. tetracycline sorbed tin(IV) molybdophosphate (TC-TMP) are described. The poly( vinyl chloride) matrix membrane electrode of the resin exhibits good potentiometric response for Al^III over a wide concentration range (10^-5 to 10^-1 M) with a slope of 22.6 mV/decade. The sensor response is stable for at least 2 years. The sensor offers the advantages of significantly high thermal stability and resistivity towards redox reagents and strong mineral acids. Good selectivity for Aim in comparison with alkaline, transition and heavy metal ions and minimal interference are caused by Hg²⁺ and Ba²⁺, which are also known to interference with other aluminum membrane sensor. The proposed sensor displays a useful analytical response with excellent reproducibility, good precision, low detection limit and applicability use in aqueous solutions of pH 2-8 and in partially non-aqueous medium with up to 10% (v/v) organic contents. The proposed electrode has been utilized as an end point indicator electrode in potentiometric titrations of Al^III with EDTA and applied successfully for the determination of aluminum in real samples also.