Original scientific paper
https://doi.org/10.5599/jese.3261
Rapid and sensitive electrochemical determination of phosphate ions using a multi-walled carbon nanotube carbon paste electrode
Qendresa Istrefi
orcid.org/0009-0004-7240-2874
; Department of Pharmacy, Faculty of Technical Medical Sciences, Western Balkans University, Tirana, Albania
*
Nevila Broli
; Department of Chemistry, Faculty of Natural Sciences, University of Tirana, Tirana, Albania
Loreta Vallja
; Department of Chemistry, Faculty of Natural Sciences, University of Tirana, Tirana, Albania
Sonila Duka
; Department of Chemistry, Faculty of Natural Sciences, University of Tirana, Tirana, Albania
Sadik Cenolli
orcid.org/0000-0002-8802-356X
; Department of Chemistry, Faculty of Natural Sciences, University of Tirana, Tirana, Albania
* Corresponding author.
Abstract
Phosphates are widely used in food as texture modifiers, preservatives and flavour enhancers, while excessive intake may negatively affect human health and the environment. Consequently, there is a growing demand for low-cost, portable, and reliable tools for phosphate monitoring in food and water samples. In this work, an electrochemical sensor based on a multi-walled carbon nanotube (MWCNT) modified carbon paste electrode (CPE) was developed for phosphate determination. Phosphate detection was based on the electrochemical reduction of an electroactive phosphomolybdate complex formed in acidic medium (50 mM sulfuric acid). Key analytical parameters, including solution acidity and complexation time, were optimized to enhance sensor performance. Carbon nanotube modification significantly enhanced the electrochemical response. While the bare CPE shows weak, poorly defined redox peaks due to limited electron transfer and low surface area, MWCNT-modified CPE exhibits well-defined peaks with ~6-fold higher current, reflecting improved sensitivity, faster electron transfer, and better peak separation. Using square-wave voltammetry, the sensor exhibited a linear response in the phosphate concentration range of 3.1 to 21.7 mg L⁻¹, with a detection limit of 0.03 mg L⁻¹ and a response time of approximately 10 s. The sensor was successfully applied to real sausage samples, yielding recoveries of 94.6 to 97.2 % with relative standard deviation values below 5 %. The presented MWCNT-CPE sensor provides a cost-effective, portable and simple device for fast and reliable in situ detection of phosphate in food and water samples.
Keywords
Phosphate anion sensing; nanomaterial-modified electrode; phosphomolybdate complex; voltammetric methods; real food samples
Hrčak ID:
346192
URI
Publication date:
5.4.2026.
Visits: 201 *