Abstract
The increasing concerns about food safety urged the desire to develop rapid and sensitive sensors for the detection of food contaminants such as pesticides. We described a reproducible and reliable screen printed carbon electrode (SPCE) modified with graphene oxide nanoribbons (GONRs) for sensitive determination of methyl parathion. The GONRs were prepared from carbon nanotubes (CNTs) and characterized by TEM, SEM, XRD, FT-IR, Raman, impedance and electrochemical techniques. Compared with CNTs, GONRs possess rich edge chemistry and abundant functional groups, higher area-normalized edge-plane structures and chemically active sites. As a result, GONRs/SPCE exhibits significantly improved electrocatalytic ability to methyl parathion in comparison with CNTs. The sensor exhibited two linear ranges; (1) 100 nM to 100 mu M with sensitivity of 1.804 mu A mu M-1 cm(2), (2) 100 mu M to 2500 mu M with sensitivity of 0.8587 mu A mu M-1 cm(2). The detection limit was 0.5 nM (S/N = 3). The combined advantages of SPCE and GONRs make this method suitable for food robust real-time food analysis. The method is successful in the determination of methyl parathion in Ugli and tomato fruits, Beetroot and Broccoli indicating its excellent practical applicability. The other advantages of the electrodes are excellent stability, repeatability, reproducibility and high selectivity. (C) 2017 The Electrochemical Society. All rights reserved.