A novel gadolinium ion-selective membrane electrode based on 2-(4-phenyl-1, 3-thiazol-2-yliminomethyl) phenol

A new gadolinium(III) selective electrode has been developed from poly vinyl chloride (PVC) matrix membrane which is based on synthesized neutral carrier [L1] 2-(2-aminothiazol-4-yl)phenol and [L2] 2-(4-phenyl-1,3-thiazol-2-yliminomethyl)phenol as ionophores. The membrane having a composition of ionophore (L2):PVC:plasticizer (acetophenone):additive (sodium tetraphenylborate) in the ratio of 5:33:60:2 exhibited calibration performance over a wide range of concentration of gadolinium (9.38 × 10−7 to 1.0 × 10−2 M) and exhibited a Nernst slope of 19.5 ± 0.5 mV per decade of Gd(III) activity. It exhibited a quick response time of 8 s and its potential response was independent of pH across the pH range of 3.5–8.5. The membrane can be used with a good reproducibility over a period of 3 months. Membrane sensor was used as a indicator electrode for determination of end point in potentiometric titration of Gd (III) ion with EDTA. The proposed membrane electrodes were successfully applied for the determination of the concentration of gadolinium (III) ion in a mineral sample.

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► A new ISE based on 2-(4-phenyl-1,3-thiazol-2-yliminomethyl) phenol for Gd3+ is reported.
► The response time of the sensor is 8 s and can be used over a period of 3 months.
► The linear range of the electrode is 9.38 × 10−7 to 1.0 × 10−2.
► The proposed electrode works well in a wide pH range 3.5–8.5.