Preparation of ethambutol-copper(II) complex and fabrication of PVC based membrane potentiometric sensor for copper

Copper(II) complex of ethambutol (1) was prepared and used in the fabrication Of Cu2+ selective ISE membrane. The membrane having Cu(II)-ethambutol complex (1) as electroactive material, along with sodium tetraphenylborate (NaTPB) as anion discriminator, dioctylphthalate (DOP) as plasticizer in poly(vinyl chloride) (PVC) matrix in the percentage ratio 6:2-190:200 (I:NaTPB:DOP:PVC) (w/w) gave a linear response in the concentration range 7.94 x 10(-6) to 1.0 X 10(-1) M Of Cu2+ with a slope of 29.9 +/- 0.2 mV per decade of activity and a fast response time of 11 +/- 2 s. The sensor works well in the pH range 2.1-6.3 and could be satisfactorily used in presence of 40% (v/v) methanol, ethanol and acetone and is-selective for copper over a large number of cations with slight interference from Na+ and Co2+ if present at a level greater than or equal to 1.5 x 10(-5) and 6.5 x 10(-5) M, respectively. It works well over a period of 6 months and can also be used as indicator electrode for the end point determination in the potentiometric titration of Cu 2+ against EDTA as well as in the determination of Cu2+ in real samples. (C) 2003 Elsevier Science B.V. All rights reserved.