Summary: | Based on the former experience on the design and construction of metal ions sensors, especially those of high sensitivity for lanthanides, (2-oxo-1,2-diphenylethylidene)-N-phenylhydrazinecarbothioamide (PHCT) was used to construct a Lu3+ PVC sensor exhibiting a Nernstian slope of 19.8±0.3 mV dec-1. The sensor was found to function well over a concentration range of 1.0×10-2 and 1.0×10-6 mol L-1 of the target ion with a detection limit of 6.8×10-7 mol L-1. The sensor selectivity against many common alkaline, alkaline earth, transition, heavy metals and specially lanthanide ions was very good and it functioned well in the pH range 2.5–8.7. Having a lifetime of at least 2 months and a short response time of ≈ 5 s, the sensor was successfully used as an indicator electrode in the potentiometric titration of Lu3+.
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