Ultrasensitive and selective electrochemical detection of Sudan I based on platinum nanoparticles functionalized cobalt trioxide and carbon nanotubes derived zeolitic imidazolate frameworks

Ultrasensitive determination of Sudan I is critically important for food products due to its potential carcinogenicity. Herein, an electrochemical sensor was developed for Sudan I detection by using nanocomposites-based glassy carbon electrodes (GCE). Cobalt trioxides (Co 3 O 4 ) dodecahedron were initially derived from zeolitic imidazolate frameworks (ZIF) and interconnected by carbon nanotubes (CNTs). After that, the Co 3 O 4 -CNTs complexes were functionalized with platinum nanoparticles (PtNPs), giving rise to a hierarchic system (PtNPs@Co 3 O 4 -CNTs/GCE) ultrasensitive to the cooperative binding activity of Sudan I. The electrochemical responses of as-proposed PtNPs@Co 3 O 4 -CNTs/GCE sensors have been evaluated toward Sudan I detection under different optimum conditions. Especially, the obtained results demonstrated that the Pt 4.5 NPs@(Co 3 O 4 ) 1 -(CNTs) 1 /GCE sensor exhibits the superior electrochemical responses with high sensitivity (27870 μA·mM −1 ·cm −2 ), wide linear range (0.03 μM-100 μM) and low limit of detection (0.005 μM, S/N = 3). These results are promising for the development of high performance sensors of Sudan I which can be used for various food applications.