One-pot synthesis of nitrogen doped graphene-thionine-gold nanoparticles composite for electrochemical sensing of diethylstilbestrol and H2O2

In this work, a facile, one-pot, and green synthetic approach was proposed to prepare a novel nanocomposite of nitrogen doped graphene-thionine-gold nanoparticles (NG-Thi-AuNPs), which was then modified on electrode to fabricate an electrochemical sensor for diethylstilbestrol (DES) accurate and reliable detection based on ratiometric strategy. The synthesized NG-Thi-AuNPs was characterized by transmission electron microscope, scanning electron microscope, Fourier transform infrared spectrum, and X-ray diffraction. Due to the merits of good conductivity and high electroactive surface of NG and AuNPs, as well as the synergistic interaction toward DES, the nanocomposite showed high sensitivity for DES detection. Moreover, the modified Thi exhibited a constant current response regardless how the DES concentration changed, which made Thi to be a good inner reference to improve the accuracy and reliability of the sensor. Thus, a ratiometric signal (Delta i(DES)/Delta i(Thi)) was measured and calculated for DES detection with a wide linear range and a low limit of detection of 5.0 x 10(-8) - 8.0 x 10(-5) mol/L and 9.6 x 10(-9) mol/L, respectively. Due to the excellent conductivity and high electrocatalytical activity of the nanocomposite, the sensor was employed for the sensitive detection of H2O2 with the linear range of 5.0 x 10(-7) - 1.0 x 10(-2) mol/L. With the good anti-interference, reproducibility, and stability, the prepared sensor was successfully used for real samples determination.