Shiquan Xiong

Electrochemical Detection of Pb(II) by Glassy Carbon Electrode Modified with Amine-Functionalized Magnetite Nanoparticles

An amine-Fe3O4 modified glassy carbon (GC) electrode was constructed for detecting Pb(II) ions in wastewater. The electrode was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Square wave anodic stripping voltammetry (SWASV) was used to detect the Pb(II), and the detection limit of Pb(II) was 0.15 µM. The sensitivity of the electrode to detect Pb(II) was about 10.07 µA/µM, with a correlation coefficient of 0.991, which was approximately 10 times bigger than that of a pure Fe3O4 modified electrode. The electrode also showed good selectivity and stability. This results indicated that the amine-magnetite material could have some potential applications in heavy metal ions detection in wastewater.

Detection of di(2-ethylhexyl)phthalate through graphene–β-cyclodextrin composites by electrochemical impedance spectroscopy

A β-cyclodextrin–graphene (β-CD–G) hybrid composite modified glassy carbon electrode for the first time was used for electrochemically detecting di(2-ethylhexyl)phthalate (DEHP), based on the inclusion of DEHP into β-CD. The electrode was characterized by cyclic voltammetry and electrochemical impedance spectroscopy. At the composites electrode, the impedance value increased linearly with the increasing DEHP concentration in the range of 2 μM to 18 μM, the limit of detection was 0.12 μM (3σ method), with a correlation coefficient of 0.998. The electrode showed good selectivity, reproducibility and stability. Obviously, the collected amounts of DEHP by β-CD–G could be detected through this electrochemical method. Furthermore, this simple and low-cost sensing platform can in principle be extended to the detection of other phthalate esters which can form host–guest complexes with cyclodextrin.

Preparation of an amino functionalized Fe3O4/Gd2O3 network composite and application in electrochemical detection of Cu2+

A Fe3O4/Gd2O3 nanocomposite grafted with polyethyleneimine (PEI) molecules was prepared using a one-pot synthesis method. Through this amino functionalized nanocomposite, a selective and ultra-trace electrochemical sensor for Cu2+ was constructed. The electrochemical performances of the sensor were demonstrated by square wave anodic stripping voltammetry (SWASV). Parameters such as the supporting electrolyte, pH of solution, deposition time, and deposition potential for the sensor were optimized. The sensor linearly responded to Cu2+ concentration in the wide range from 6 to 1680 nM with a detection limit of 0.4 nM (3δ method), indicating that this amino functionalized Fe3O4/Gd2O3 composite could be a promising candidate material for the detection of Cu2+.

Facile and quantitative electrochemical detection of yeast cell apoptosis

An electrochemical method based on square wave anodic stripping voltammetry (SWASV) was developed to detect the apoptosis of yeast cells conveniently and quantitatively through the high affinity between Cu2+ and phosphatidylserine (PS) translocated from the inner to the outer plasma membrane of the apoptotic cells. The combination of negatively charged PS and Cu2+ could decrease the electrochemical response of Cu2+ on the electrode. The results showed that the apoptotic rates of cells could be detected quantitatively through the variations of peak currents of Cu2+ by SWASV, and agreed well with those obtained through traditional flow cytometry detection. This work thus may provide a novel, simple, immediate and accurate detection method for cell apoptosis.

Electrochemical detection of Cu(II) using amino-functionalized MgFe2O4/Reduced graphene oxide composite

In this study, an amino-functionalized MgFe2O4/reduced graphene oxide (rGO) composite was prepared by the combination of MgFe2O4/rGO and 1,6-hexanediamine (HDA) and employed for the electrochemical detection of Cu(II) ions. The composite was obtained through a one-pot method, and it was characterized by SEM, XRD, FT-IR and electrochemical methods. Some important parameters such as pH of solution, amount of modification, deposition time, and deposition potential were optimized. The determination of Cu(II) ions was performed using HDA/rGO/MgFe2O4, rGO/MgFe2O4 and MgFe2O4via square-wave anodic stripping voltammetry. The lowest detection limit obtained was 0.2 nM, and the sensitivity was 0.0172 μA nM−1. The proposed electrode was also used for the detection of Cu(II) ions in soil sample. Overall, the proposed method could provide a reference for the detection of metal ions.