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

Polyethylene glycol functionalized CuO/rGO nanocomposite based electrochemical sensor for ultra-sensitive electro-oxidation of bromoxynil in vegetables

Jamil A. Buledi, Madeeha Batool, Sidra Ameen, Amber R. Solangi, Arfana Mallah, Ismail Murat Palaybik, Syed Tufail H. Sherazi, and Saba Ali

National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, Pakistan

E-mail: ambersolangi@gmail.com

Received: 8 April 2023  Accepted: 29 July 2023

Abstract:

Massive increase in the herbicide production to control pests and high yield of crops has been a serious threat to human life. In an attempt to monitor the low concentration of bromoxynil herbicide in the food samples, for the first time, we have developed an effective chemically modified electrochemical sensor based on polyethylene glycol functionalized copper oxide/recued graphene oxide platinum electrode (PEG/CuO/rGO/PtE). Advanced analytical tools successfully explored the crystalline structure of PEG/CuO/rGO nanocomposite with exfoliated flakes like surface texture and average size of 46.7 nm. The EDX analysis confirmed the presence of carbon 52.1%, copper 26.1% and oxygen 21.8%. Moreover, high resolution TEM images clearly manifested the flakes like internal texture of prepared nanocomposite. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry were employed to examine electrocatalytic features and charge transfer kinetics of PEG/CuO/rGO/PtE. The EIS analysis confirmed the charge transfer resistance of bare/PtE, GO/PtE and PEG/CuO/rGO/PtE as (5527 Ω), (4338 Ω) and (2173 Ω), respectively. At optimized conditions, i.e., scan rate 140 mV/s, PBS electrolyte pH-4 and potential window (0.4 to 1.2 V), the engineered PEG/CuO/rGO/PtE exhibited exceptional response for bromoxynil. Under two different concentration ranges, i.e., from 0.05 to 4.05 µM and 15 to 90 µM, the proposed sensor manifested low possible LOD for bromoxynil calculated as 0.0044 µM and 0.116 µM, respectively. Real application of prepared sensor was tested in vegetable samples of potato and spinach. The PEG/CuO/rGO/PtE displayed acceptable percent recoveries for both potato and spinach vegetable samples which highlights the effectiveness of engineered electrochemical sensor. Good stability, anti-interference profile and reliability of fabricated sensor make it a promising probe that could be used at commercial levels.

Keywords: CuO-NPs; Graphene oxide; Polyethylene glycol; Bromoxynil, herbicides and environmental pollution

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-023-03012-x

Chemical Papers 77 (11) 7215–7223 (2023)