Construction of strontium PVC-membrane sensor based on salicylaldehyde thiosemicarbazone

This work introduces a unique ionophore for the selective determination of Sr2+ ions. The ionophore, salicylaldehyde thiosemicarbazone (ST), presented a high affinity toward the strontium cations. The demonstrated characteristics of the sensor included a linear dynamic range between 1.010-6 and 1.010-2M with a near Nernstian slope of 29.40.5mV per decade, a detection limit of 4.810-7M, and a very good selectivity for Sr2+ over other cations in a wide pH range (2.8-10.4). The sensor possessed the advantages of short conditioning time, fast response time (10s), and, especially, good selectivity toward the transition and heavy metal ions as well as some mono, di, and trivalent cations. Concerning the electrode lifetime, no considerable potential divergence was noticed for at least 10 weeks. The developed sensor was successfully used as an indicator electrode in the Sr2+ titration with EDTA from binary mixtures, and the Sr2+ monitoring in mixtures of three and five different ions.