title: Hydroxy-thioxanthones as suitable neutral ionophores for the preparation of PVC-membrane potentiometric sensors for Al(III) ion.
abstract: The complexation of five recently synthesized hydroxy-thioxanthone derivatives with Al3+ ion was studied in a methanol solution spectrophotometrically, and the stepwise formation constants of the resulting 1:1 and 2:1 (ligand-to-metal) complexes were evaluated. The suitability of the thioxanthone derivatives as neutral ionophores for the preparation of a new Al3+ ion-selective PVC-membrane electrode was investigated, and 1-hydroxy-3-methyl-thiocanthone was selected as the best compound for this purpose. The prepared electrode exhibits a Nernstian response for Al3+ ions over a wide concentration range (2.0 x 10(-2) to 2.0 x 10(-6) M), with a limit of detection of 1.0 x 10(-6) M. It has a very fast response time of about 5 s and can be used for at least 3 months without any considerable divergence in the potentials. The proposed membrane sensor revealed very good selectivities for Al3+ over a wide variety of other metal ions, and could be used at a working pH range of 3.4 - 5.0. It was used as an indicator electrode in potentiometric titration of aluminum ions with EDTA, and in the determination of Al3+ in different real samples.
authors.affiliation: Department of Chemistry, Razi University, Kermanshah, Iran. mshamsipur@yahoo.com
authors.forename: Mojtaba
authors.initials: M
authors.lastname: Shamsipur
authors.forename: Sohrab
authors.initials: S
authors.lastname: Ershad
authors.forename: Absollah
authors.initials: A
authors.lastname: Yari
authors.forename: Hashem
authors.initials: H
authors.lastname: Sharghi
authors.forename: Ali Reza
authors.initials: AR
authors.lastname: Salimi