2,3-Diphenylquinoxaline-4′,4″-dioxytriethylene glycol as a sensing and selective material for construction of strontium-PVC membrane sensor

The PVC membrane containing 2,3-diphenylquinoxaline-4′,4″-dioxytriethylene glycol (PQTEG) as a suitable ionophore, presents a linear dynamic range of 1.0 × 10− 6–1.0 × 10− 2 M with a Nernstian slope of 29.9 mV per decade and a detection limit of 6.7 × 10− 7 M. The response time is quick (smaller than 15 s), it can be used in the pH range of 4.1–8.9 and its duration is at least 55 days without noticing any considerable potential divergence. The proposed electrode has very good selectivity with respect to all common alkali, alkaline earth in the range of − 3.28 to − 4.00, and for transition metal ions in the range of − 3.38 to − 4.00. It was successfully applied as an indicator electrode in potentiometric titration of Sr(II) ions with EDTA.