Electrochemical determination diethylstilbestrol by a single-walled carbon nanotube/platinum nanoparticle composite film electrode

A facile one-pot synthesis of magnetic iron oxide nanoparticles embed N-doped graphene modified magnetic screen printed electrode for electrochemical sensing of chloramphenicol and diethylstilbestrol

Trace determination of antibacterial agents is crucial to minimize risks of human intoxication and in the prevention of serious environmental impacts. Herein, a simple one-pot solvothermal synthesis approach for a magnetic iron oxide embed nitrogen-doped graphene (MIO@NG) nanohybrid was fabricated without the addition of any extra reductant and its application towards ultrasensitive chloramphenicol (CAP) and diethylstilbestrol (DES) electrochemical sensor is demonstrated to screen for antibiotic residue contamination in milk samples. The prepared nanohybrid was modified on a magnetic screen-printed electrode (MSPE) to make it portable for on-site detection. The determination of two additive drugs, CAP and DES, was achieved based on the reduction current response at MIO@NG modified MSPE (MIO@NG/MSPE) to eliminate interference as far as possible. Uniform dispersed MIO nanoparticles are grown in situ on the surface of nitrogen-doped graphene sheets. The morphology of MIO@NG was confirmed by transmission electron microscopy (TEM) analysis. The chemical structure of the prepared MIO@NG was characterized by x-ray diffraction (XRD), x-ray photoemission spectroscopy (XPS), Raman spectroscopy, and extended x-ray absorption fine structure (EXAFS). Moreover, the superparamagnism property was investigated by vibrating sample magnetometry (VSM). The electrochemical properties of MIO@NG were evaluated with cyclic voltammetry (CV) and square wave voltammetry (SWV). Sensor performance was evaluated by testing the electrochemical activity of CAP and DES in the presence of interferences. The MIO@NG modified electrode presented superior electrochemical performance, including high sensitivity, high catalytic activity, ultimate sensitivity, very fast detection, selectivity, and excellent performance. The MIO@NG modified electrode demonstrated a detection limit of 10 nM for the detection of CAP and 6.5 nM for DES with satisfactory recovery in real samples.

A novel electrochemical sensor based on Fe3O4-doped nanoporous carbon for simultaneous determination of diethylstilbestrol and 17β-estradiol in toner

In this paper, Fe₃O₄-doped nanoporous carbon (Fe₃O₄-NC) was synthesized through the carbonization of Fe-porous coordination polymer (Fe-PCP), which are also known as metal-organic framework (MOF), and fabricated into an electrochemical sensor for simultaneous analysis of diethylstilbestrol (DES) and 17β-estradiol (E2) in toner. Fe₃O₄-NC was characterized by scanning electron microscope (SEM), powder X-ray diffraction (pXRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, N₂ adsorption-desorption and so on. It is of great practical significance to achieve the simultaneous determination of the two estrogens because estrogens are co-existing in many real samples. The simultaneous determination of two common estrogens, DES and E2, was achieved through electro-catalytically oxidization at a Fe₃O₄-NC modified glassy carbon electrode (Fe₃O₄-NC/GCE). The peak currents of DES and E2 increased linearly as their concentrations increasing from 0.01 to 12 μmol/L and from 0.01 to 20 μmol/L, with detection limits of 4.6 nmol/L and 4.9 nmol/L (S/N = 3), respectively. This work was focused on the simultaneous determination of the two estrogens in toner. Furthermore, the recoveries of DES and E2 were 91.2-110%, in actual toner samples. The experimental results manifest that the sensor with a stronger anti-interference ability can be used for the simultaneous detection of DES and E2 in the actual toner sample.

Liquid-phase exfoliated graphene as highly-sensitive sensor for simultaneous determination of endocrine disruptors: diethylstilbestrol and estradiol

It is quite important to develop convenient and rapid analytical methods for trace levels of endocrine disruptors because they heavily affect health and reproduction of humans and animals. Herein, graphene was easily prepared via one-step exfoliation using N-methyl-2-pyrrolidone as solvent, and then used to construct an electrochemical sensor for highly-sensitive detection of diethylstilbestrol (DES) and estradiol (E2). On the surface of prepared graphene film, two independent and greatly-increased oxidation waves were observed at 0.28V and 0.49V for DES and E2. The remarkable signal enlargements indicated that the detection sensitivity was improved significantly. The influences of pH value, amount of graphene and accumulation time on the oxidation signals of DES and E2 were discussed. As a result, a highly-sensitive and rapid electrochemical method was newly developed for simultaneous detection of DES and E2. The values of detection limit were evaluated to be 10.87 nM and 4.9 nM for DES and E2. Additionally, this new method was successfully used in lake water samples and the accuracy was satisfactory.

Graphene oxide-modified electrodes for sensitive determination of diethylstilbestrol

This paper reports an electrochemical sensor fabricated with graphene oxide (GO) modified on a chitosan-coated glassy carbon electrode (GO-CS/GCE) and its application for the detection of diethylstilbestrol (DES). It was observed that the effective electrochemical surface area of the GO modified electrode was nearly 10 times that of the bare GCE. This could be used to explain the results that the oxidation peak current of DES on the GO-CS/GCE was much larger than on the bare GCE. Under optimized conditions, the prepared electrode could be used to electrochemically detect DES according to the oxidation of the DES. Based on the technique of differential pulse voltammetry and the accumulation of DES on GO modified electrodes, the calibration curve for DES determination could be obtained with a linear range of 1.5 × 10(-8)-3.0 × 10(-5) M and an estimated detection limit of 3.0 × 10(-9) M (S/N = 3). The feasibility of the developed electrode for tablet sample analysis was investigated. Our investigation revealed that GO could significantly improve the analytical performance of electrochemical sensors.