Electrochemical Anion Sensor for Monohydrogen Phosphate Based on Nano-composite Carbon Paste

• Published in: International journal of electrochemical science Vol. 7; no. 3; pp. 2633 - 2642
• Main Authors: Norouzi, P., Ganjali, M.R., Faridbod, F., Shahtaheri, S.J., Zamani, H.A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2012
• Subjects: Ion selective electrode; Ionic liquid; Monohydrogen phosphate; Multi-walled Carbon Nanotube; Potentiometry; Sensor; Ion selective electrode; Multi-walled Carbon Nanotube; Monohydrogen phosphate; Potentiometry; Ionic liquid; Sensor
• ISSN: 1452-3981; 1452-3981
• DOI: 10.1016/S1452-3981(23)13908-3

Spectroscopic studies of the interaction between cerium acetylacetonate complex (CAA) and a number of inorganic anions showed a selective interaction between CAA and monohydrogen phosphate anion respect to the other anion tested. Therefore, CAA was used as a suitable ionophore (sensing element) in construction of a nano-composite carbon paste electrode. The nano-compoite paste was composed of 5% Multi-walled Carbon Nanotube (MWCNT), 65% graphite powder, 15% room temperature ionic liquid (RTIL) and 15% of CAA. The proposed electrode composition was selected after a series of experiments and optimizations. The sensor worked well with a Nernstian response of -29.3±0.4 mV decade-1 of HPO42- anion in a wide dynamic concentration range of 1.0×10-6-1.0×10-1 mol L-1. The electrode had relatively short response time (20 s), and it was found to produce stable responses for more than two months. It was also used for monitoring of monohydrogen phosphate ion concentration in waste water samples.