A mercury(II) ion-selective electrode based on neutral salicylaldehyde thiosemicarbazone

• Published in: Talanta (Oxford) Vol. 59; no. 1; pp. 101 - 105
• Main Authors: Mahajan, R.K, Kaur, Inderpreet, Lobana, T.S
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 02-01-2003; Oxford Elsevier
• Subjects: Analytical chemistry; Chemistry; Electrochemical methods; Exact sciences and technology; General, instrumentation; Mercury(II); Potentiometry; Sensor; Thiosemicarbazone; Mercury(II); Thiosemicarbazone; Potentiometry; Sensor; Performance evaluation; Membrane electrode; Mercury II; Selectivity; Chemical sensor; Ion selective electrode; Lifetime; Response time; Detection limit; Ionophore; Salicylates; Polyvinyl chloride; Electrochemical titration
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/S0039-9140(02)00473-3

A new ion-selective PVC membrane electrode based on salicylaldehyde thiosemicarbazone as an ionophore is developed successfully as sensor for mercury(II) ions. The electrode shows excellent potentiometric response characteristics and displays a linear log[Hg
2+] versus EMF response over a wide concentration range of 1.778×10
−6–1.0×10
−1 M with Nernstian slope of 29 mV per decade with the detection limit of 1.0×10
−6 M. The response time of the electrode is less than 30 s and the membrane electrode operates well in the pH range of 1.0–3.0. The lifetime of the sensor is about 2 months. The electrode shows better selectivity towards Hg
2+ ions in comparison with the alkali, alkaline and some heavy metal ions; most of these metal ions do not show significant interference (
K
Pot
Hg,
M values of the order of 10
−3–10
−4). The present sensor showed comparable or even better performance vis-à-vis similar PVC based ion-selective electrodes reported in literature. The sensor was also applied as an indicator electrode for potentiometric titration of Hg
2+ions with I
− and Cr
2O
7
2−.