Aluminum(III) selective potentiometric sensor based on morin in poly(vinyl chloride) matrix

Al3+ selective sensor has been fabricated from poly(vinyl chloride) (PVC) matrix membranes containing neutral carrier morin as ionophore. Best performance was exhibited by the membrane having composition as morin:PVC: sodium tetraphenyl borate: tri-n-butylphosphate in the ratio 5:150:5:150 (w/w, mg). This membrane worked well over a wide activity range of 5.0 x 10(-7) to 1.0 x 10(-1) M of Al3+, with a Nernstian slope of 19.7 +/- 10.1 mV/decade of Al3+ activity and a limit of detection 3.2 x 10(-7) M. The response time of the sensor is similar to 5 s and membrane could be used over a period of 2 months with good reproducibility. The proposed sensor works well over a pH range (3.5-5.0) and demonstrates good discriminating power over a number of mono-, di- and trivalent cations. The sensor can also be used in partially non-aqueous media having up to 20% (v/v) methanol, ethanol or acetone content with no significant change in the value of slope or working activity range. The sensor has also been used in the potentiometric titration of Al3+, with EDTA and for its determination in zinc plating mud and red mud. (C) 2007 Elsevier B.V. All rights reserved.