Graphene oxide-modified electrodes for sensitive determination of diethylstilbestrol

Abstract

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.

Graphene Quantum Dots Modified Screen‐printed Electrodes as Electroanalytical Sensing Platform for Diethylstilbestrol

“…This decrease can be attributed to the fact that some species involved in the redox processes of the DES are adsorbed on the surface of the electrode, causing the blockade and finally the decrease of the current. This behavior is already described in the literature and therefore the current values collected are always the 10 th cycle.…”

Electrochemical determination of trace pesticide residues based on multiwalled carbon nanotube grafted acryloyloxy ferrocene carboxylates with different spacers

“…The linear equation can be expressed as I p,a (10 À5 A) ¼ 2.04 lg C Mel + 25.25, with the correlation coefficient 0.9632, whilst the reduction current (I pc ) and the logarithm of the melamine concentration show a good linear relationship in a concentration range from 1 Â 10 À3 to 1 Â 10 À9 M with the linear calibration equation I p,c (10 À5 A) ¼ À2.69 lg C Mel À 33.82 (R 2 ¼ 0.9319). The limit of detection (LOD) is estimated using three times the noise, viz., signal/noise ¼ 3, together with the following equation as reported elsewhere: 45 LOD ¼ KS b /r (1) where S b is the standard deviation of the signals; K is a coefficient determined based on a certain condence level factor 3); and r is the sensitivity of the method, namely, the slope of the calibration curve. The LOD is 1.5 Â 10 À7 mol L À1 (1.9 Â 10 À2 mg L À1 ), which is low enough for the determination of trace melamine in real sample analysis.…”

Multifunctional liquid-like graphene@fe3o4hybrid nanofluid and its epoxy nanocomposites

“…However, it is another daunting challenge to prevent graphene from stacking in polymer matrixes—an inherent problem for functional polymer/graphene nanocomposites . The interface between matrix and dispersed fillers acts as a bridge of transferring mechanical stress, and hence the role of interface is crucial for functional polymer/graphene nanocomposites . Fortunately, the liquid‐like graphene@Fe 3 O 4 hybrid nanofluid starts with highly oxidized graphite, short‐chain surfactant, and long‐chain canopy, which may efficiently solve this problem.…”