ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

A novel composite electrochemical sensor doped ion-imprinted polymer based on N-methacryloyl-L-histidine/ethylene glycol dimethacrylate for ultrasensitive determination of copper (II) ions in food supplements

Cihan Topcu, Rabia Rana Yilmaz, Betul Hilal Atasoy, Ismail Ocsoy, and Vedat Yilmaz

Department of Biomedical Engineering, Faculty of Engineering and Natural Sciences, Samsun University, Samsun, Turkey

E-mail: ctopcu@gmail.com

Received: 23 January 2024  Accepted: 19 August 2024

Abstract:

In this study, a highly selective and sensitive composite electrochemical sensor based on an ion-imprinted polymer (IIP) material is reported for the potentiometric determination of ultra-trace copper (II) ions. The copper (II)-IIP was prepared by using N-methacryloyl-L-histidine chelating monomer and ethylene glycol dimethacrylate cross-linker via bulk polymerization method. The synthesized IIP was used as electroactive material (ionophore) with graphite (G) and paraffin oil (PO) for recognition of copper (II). The sensor composition was optimized for effective recognition of copper (II) by examining ratios of components used in sensor preparation. The sensor with a composition of IIP/G/PO in the ratio 30:50:20 (% w/w) exhibited an ultra-wide linear response in detection of copper (II) ions with a Nernstian slope of 32.8 ± 1.2 mV in the concentration range of 1.0 × 10^–8—1.0 × 10^–1 mol L⁻¹ (R² = 0.9978), and a response time of 6 s was achieved with the optimized sensor. The potential response was stable within the pH range from 3.0 to 8.0. The standard deviation of the sensor was below 1.2 mV for 1.0 × 10^–2, 1.0 × 10^–3, and 1.0 × 10^–4 mol L⁻¹ copper (II) solutions. The sensor afforded a highly selective potentiometric response to Cu²⁺ with respect to Rb⁺, K⁺, Li⁺, Na⁺, NH₄⁺, Cs⁺, Ba²⁺, Co²⁺, Mg²⁺, Zn²⁺, Ni²⁺, Pb²⁺, Cr³⁺, Sr²⁺, Al³⁺, and Ca²⁺ ions. The developed sensor was used as an indicator sensor for the potentiometric titrations of copper (II) with EDTA and successfully applied to the determination of copper (II) in tap water, river water, dam lake water samples, coin samples, and food supplements (multivitamin/multielement).

Keywords: Composite electrochemical sensor; Copper (II) selective sensor; Potentiometry; Ion-imprinted polymers; Potentiometric copper (II) determination; Copper in multivitamin/multielement supplements

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-024-03664-3

Chemical Papers 78 (15) 8245–8260 (2024)