Abstract
In this study, a new ion-selective electrode for Sm3+ is described, illustrating 2-[(E)-1-(1H-pyrrol-2-yl)methylidene]-1-hydrazinecarbothioamide (PMH) in a poly(vinylchloride) (PVC) membrane with nitrobenzene (NB) as a plasticizer and sodium tetraphenyl borate (NaTPB) as an anionic additive. The proposed sensor exhibited a Nernstian response for Sm3+ ions over a wide concentration range between 1.0 × 10−2 and 1 × 10−6 M, with a detection limit of 5.2 × 10−7 M in the pH range of 4.2–8.5. Moreover, the sensor displayed the Nernstian slope of 19.8 ± 0.3 mV per decade, having a fast response time within 10 s over the entire concentration range. This electrode presented very good selectivity and sensitivity toward the Sm3+ ions over a wide variety of cations, including alkali, alkaline earth, transition-metal, and heavy-metal ions. It was used as an indicator electrode in the potentiometric titration of Sm3+ ions with EDTA. The membrane sensor was also applied to the determination of fluoride ions in mouthwash samples.
Acknowledgments
The authors acknowledge the kind financial support provided by the Research Council of Quchan University for the preparation of this study.
Notes
a Proposed Sm3+ sensor.
b Results are based on three measurements.