Efficient synthesis of graphene-multiwalled carbon nanotubes nanocomposite and its application in electrochemical sensing of diethylstilbestrol

Herein, a sensitive voltammetric method for the determination of diethylstilbestrol (DES), illegally used as a growth promoter in animal husbandry, was developed using electrochemically reduced graphene oxide-multiwalled carbon nanotubes (ERGO-MWCNTs) modified electrode. The incorporated multiwalled carbon nanotubes (MWCNTs) served as electrical conducting wires, which could facilitate the electrochemical reduction of graphene oxide (GO). Compared to either electrochemically reduced graphene oxide (ERGO) or MWCNTs, integrating these nanostructures resulted in a strong synergistic effect between the two materials consequently leading to a superior hybrid material with higher activity for the electro-oxidation of DES. The electron transfer coefficient (α), the standard rate constant (k_s), electrochemically effective surface area (A) and the saturating absorption capacity (Г_s) were calculated. Under the optimized conditions, ERGO-MWCNTs modified electrode exhibited better linearity than either ERGO or MWCNTs over ranges from 0.01 to 40 μM with the detection limit of 3 nM (S/N = 3). Moreover, the proposed method was successfully applied to determine DES in real sample and satisfactory results were obtained. The results showed that the modified electrode exhibits an excellent catalytic activity, good sensitivity and reproducibility.