Ge Song

A supersensitive sensor for rutin detection based on multi-walled carbon nanotubes and gold nanoparticles modified carbon paste electrodes

A new voltammetric sensor was designed by covering a layer of gold nanoparticles (AuNPs) on a carbon paste electrode that was pre-mixed in some multi-walled carbon nanotubes (MWCNT). This sensor exhibited super sensitive detection of the electroactive flavonoid rutin due to the large surface area and good conductivity of MWCNT and AuNPs. Cyclic voltammetry curves at various scan rates and pH were recorded to investigate the redox properties of rutin. Further experiments demonstrated that the oxidative peaks increased linearly with rutin concentrations in the ranges of 4.0 × 10−10 to 1.0 × 10−8 mol L−1 and 2.0 × 10−8 to 1.0 × 10−6 mol L−1 with a limit of detection of 4.0 × 10−11 mol L−1. The method was successfully applied to detect rutin in medicine tablets with satisfactory results.

Sensitive voltammetric sensor for bergenin based on poly(L-lysine)/graphene modified glassy carbon electrode

A sensitive and novel electrochemical sensor for detection of bergenin by linear sweep voltammetry (LSV) is presented. This sensor was fabricated by dripping well-dispersed graphene onto glassy carbon electrode (GCE) surface firstly, and then poly(L-lysine) films were subsequently electropolymerized on it to prepare poly(L-lysine)/graphene/GCE. The dynamic detection range of this sensor to bergenin was 4.0 × 10−8 to 5.0 × 10−6 mol L−1 and 6.0 × 10−6 to 1.7 × 10−5 mol L−1, with the detection limit of 1.0 × 10−8 mol L−1. A new voltammetric method for determination of bergenin was erected and shows high sensitivity and selectivity, wider linear relationship, very easy surface update and good stability. The proposed sensors were tested for bergenin detection in pharmaceutical tablets with high accuracy and satisfactory recovery results was obtained. In addition, the oxidation mechanism is proposed and discussed, which could be a reference for the pharmacological action of bergenin in clinical studies.

Sensitive determination of pesticide imidacloprid using a glassy carbon electrode modified with a film composed of multi-walled carbon nanotubes and poly(aspartic acid)

A new voltammetric sensor, based on multi-walled carbon nanotubes (MWCNTs) composite poly(aspartic acid) film modified glassy carbon electrode, was fabricated and used for determination of pesticide imidacloprid. The synergistic effect of MWCNTs and the polymer resulted in a significantly improved electrochemical response (in terms of sensitivity, accuracy and analytical range) towards imidacloprid. Under selective conditions, the determination linear range was from 1.53 × 10−5 g L−1 up to 1.53 × 10−2 g L−1 with a detection limit of 1.15 × 10−5 g L−1 (S/N = 3). The sensor also had an easily renewable surface, good fabrication reproducibility, and inherent stability. Moreover, satisfactory results were obtained with complex samples and demonstrate the reliability of the proposed method.

A novel self-assembly voltammetric sensor for malachite green based on ethylenediamine and graphene oxide

A novel self-assembly modified carbon paste electrode based on ethylenediamine and graphene oxide was proposed as a highly sensitive electrochemical sensor for detection of malachite green. The manufacturing operation of the recommended sensor was characterized by cyclic voltammetry and electrochemical impedance spectroscopy. The electrochemical response of malachite green at this sensor was investigated in detail and a new electroanalytical method was erected with high sensitivity and selectivity. The proposed method exhibited good linearity for malachite green over the range from 8.0 × 10−9 mol L−1 to 8.0 × 10−7 mol L−1 with the detection limit of 5 × 10−9 mol L−1 (S/N = 3) by differential pulse voltammetry under optimum conditions. Finally, the practical application was proven by spiking malachite green standards in lake water with recoveries ranging from 98.80% to 101.10%, showing a satisfactory result.