Glassy carbon electrodes modified with reduced graphene oxide-MoS(2)-poly (3, 4-ethylene dioxythiophene) nanocomposites for the non-enzymatic detection of nitrite in water and milk.

The detrimental effect of (NO2-) on environment, a sensitive and selective detection of nitrite (NO2-) ions with point-to-care device is need to be fabricated. Herein, we report the non-enzymatic nitrite sensor using a novel reduced graphene oxide/molybdenum disulfide/poly (3, 4-ethylene dioxythiophene) (rGO/MoS2/PEDOT) nanocomposite electrode. The rGO/MoS2/PEDOT nanocomposite was synthesized using facile and cost-effective hydrothermal and polymerization approaches. The characteristics of rGO-MoS2-PEDOT nanocomposite was investigated by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Raman, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) analyses. The rGO-MoS2-PEDOT nanocomposite modified glassy carbon electrode (GCE) was directly used for electrocatalytic detection of nitrite ions present in the solution. TEM images show the PEDOT nanoparticles with an average size of 100-120 nm are uniformly covered on the outer face of rGO-MoS2 nanosheets. The interaction between the PEDOT and rGO-MoS2 is evidenced in the FTIR, XRD and XPS studies, and they produced synergistic effect, resulting enhanced electrocatalytic performance activity towards oxidation of nitrite. Under optimized conditions, the fabricated electrode exhibited remarkably good sensitivity (874.19 μA μM-1 cm-2), low detection limit (LOD) (0.059 μM, S/N = 3), wide linear range (0.001-1 mM) of nitrite with desirable selectivity, long-term stability and reproducibility. Furthermore, the practical feasibility of the fabricated sensor is validated by the successful detection of nitrite ion in some water and milk samples with excellent correlation. Thus, feasible easier synthesis method was adopted first time to fabricate rGO-MoS2-PEDOT nanocomposite nitrite sensor in the milk and water samples with enhanced selectivity, sensitivity and LOD.

Madhuvilakku R ，Alagar S ，Mariappan R ，Piraman S ... -  《-》

Electrochemical synthesis of multilayered PEDOT/PEDOT-SH/Au nanocomposites for electrochemical sensing of nitrite.

Ge Y ，Jamal R ，Zhang R ，Zhang W ，Yu Z ，Yan Y ，Liu Y ，Abdiryim T ... -  《-》

Electrocatalytic determination of nitrite based on straw cellulose/molybdenum sulfide nanocomposite.

Cellulose is the most abundant, renewable, biodegradable natural polymer resource on earth, which can be a good substrate for catalysis. In this work, straw cellulose has been oxidized through 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation, and then a TEMPO oxidized straw cellulose/molybdenum sulfide (TOSC-MoS2) composite has been synthesized via a hydrothermal method. Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) analysis confirm that TOSC and MoS2 have successfully composited. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images show the TOSC as a carbon nanotube-like structure and edged MoS2 grows on the TOSC substrate. The TOSC-MoS2 modified glassy carbon electrode (GCE) is used as a simple and non-enzymatic electrochemical sensor. Cyclic Voltammetry (CV) result shows TOSC-MoS2 has excellent electrocatalytic activity for the oxidation of nitrite. The amperometric response result indicates the TOSC-MoS2 modified GCE can be used to determine nitrite concentration in wide linear ranges of 6.0-3140 and 3140-4200µM with a detection limit of 2.0µM. The proposed sensor has good anti-interference property. Real sample analysis and the electrocatalytic mechanism have also been presented.

Wang H ，Wen F ，Chen Y ，Sun T ，Meng Y ，Zhang Y ... -  《-》

A novel reduced graphene oxide/molybdenum disulfide/polyaniline nanocomposite-based electrochemical aptasensor for detection of aflatoxin B(1).

Geleta GS ，Zhao Z ，Wang Z 《-》

A novel electrochemical sensor based on silver/halloysite nanotube/molybdenum disulfide nanocomposite for efficient nitrite sensing.

In the present study, the silver/halloysite nanotube/molybdenum disulfide (Ag/HNT/MoS2) nanocomposite was successfully synthesized. For this purpose, the lumen of HNTs was firstly modified by silver to generate Ag nanorods via chemical process and then the MoS2 layers deposited on the Ag/HNT nanocomposite by hydrothermal method. The characterization of Ag/HNT/MoS2 nanocomposite were investigated by field emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) analyses. The nanocomposite modified carbon paste electrode (CPE) was applied for the electrocatalytic detection of nitrite in aqueous solutions. It was demonstrated that the treatment of HNTs with Ag and MoS2 materials enhanced the catalytic performance of modified CPE. At optimal experimental conditions, the designed sensor displayed remarkable sensing ability toward nitrite oxidation, offering a good linearity from 2 to 425 µM. The limit of detection (LOD) of the proposed strategy was estimated to be 0.7 µM based S/N = 3. The good reproducibility, acceptable stability, fast response time and anti-interference performance of the proposed assay suggests that the modified CPE has great potential working as a nitrite electrochemical sensor for environmental applications.

Ghanei-Motlagh M ，Taher MA 《-》