nhui Yi

Highly sensitive and simultaneous electrochemical determination of 2-aminophenol and 4-aminophenol based on poly(l-arginine)-β-cyclodextrin/carbon nanotubes@graphene nanoribbons modified electrode

Owing to the similar characteristics and physiochemical property of 2-aminophenol (2-AP) and 4-aminophenol (4-AP), the highly sensitive simultaneous electrochemical determination of 2- and 4-AP is a great challenge. In this paper, by electropolymerizing β-cyclodextrin (β-CD) and l-arginine (l-Arg) on the surface of carbon nanotubes@graphene nanoribbons (CNTs@GNRs) core-shell heterostructure, a P-β-CD-l-Arg/CNTs@GNRs nanohybrid modified electrode was prepared successfully, and it could exhibit the synergetic effects of β-CD (high host-guest recognition and enrichment ability), l-Arg (excellent electrocatalytic activity) and CNTs@GNRs (prominent electrochemical properties and large surface area), the P-β-CD-l-Arg/CNTs@GNRs modified electrode was used in the electrochemical determination of 2- and 4-AP, the results demonstrated that the highly sensitive and simultaneous determination of 2- and 4-AP is successfully achieved and the modified electrode has a linear response range of 25.0-1300.0 nM for both 2- and 4-AP, and the detection limits of 2- and 4-AP obtained in this work are 6.2 and 3.5 nM, respectively.

Nitrogen-doped hollow carbon spheres wrapped with graphene nanostructure for highly sensitive electrochemical sensing of parachlorophenol.

Owing to awfully harmful to the environment and human health, the qualitative and quantitative determination of parachlorophenol (PCP) is of great significance. In this paper, by using silica@polydopamine as template, nitrogen-doped hollow carbon spheres wrapped with reduced graphene oxide (NHCNS@RG) nanostructure was prepared successfully via a self-assembly approach due to the electrostatic interaction, and the obtained NHCNS@RG could exhibit the unique properties of NHCNS and RG: the NHCNS could impede the aggregation tendency of RG and possess high electrocatalytic activity; the RG enlarges the contacting area and offers many area-normalized edge-plane structures and active sites. Scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, X-ray diffraction and electrochemical method were used to characterize the morphology and structure of NHCNS@RG. Then, the NHCNS@RG hybrids were applied for the electrochemical sensing of PCP, under the optimized conditions, the detection limit of PCP obtained in this work is 0.01μM and the linear range is 0.03-38.00μM.

Sensitive electrochemical determination of rhodamine B based on cyclodextrin-functionalized nanogold/hollow carbon nanospheres

Due to being harmful to the human health, the qualitative and quantitative determination of rhodamine B (RhB) is of great significance. In this paper, per-6-thio-β-cyclodextrin functionalized nanogold/hollow carbon nanospheres (β-CD-AuNPs/HCNS) nanohybrids were prepared and then applied successfully for the highly sensitive electrochemical detection of RhB. Due to the synergetic effects from the HCNS (excellent electrochemical properties and large surface area), β-CD (high host–guest recognition and water-solubility) and AuNPs (excellent electrocatalytic activity), the oxidation peak currents of RhB on the β-CD-AuNPs/HCNS modified glassy carbon electrode (GCE) are much higher than those on the AuNPs/HCNS/GCE and bare GCE. The β-CD-AuNPs/HCNS/GCE has a linear response range of 4.79–958.00 μg L−1 with a detection limit of 0.96 μg L−1 for RhB.

3,4,9,10-Perylene Tetracarboxylic Acid Noncovalently Modified Multiwalled Carbon Nanotubes: Synthesis, Characterization, and Application for Electrochemical Determination of 2-Aminonaphthalene

Carbon nanotubes have been intensively studied for their diverse applications but are insoluble in water. In this paper, 3,4,9,10-perylene tetracarboxylic acid noncovalently modified multiwalled carbon nanotubes were prepared by a facile approach and applied successfully for electrochemical determination of 2-aminonaphthalene. Infrared spectroscopy, Raman spectroscopy, thermogravimetric analysis, and electrochemical methods were used to characterize the hybridized nanotubes. The results reveal that the hybrids exhibit high dispersibility in water, and a glassy carbon electrode modified by the hybrids displayed a higher electrochemical response toward 2-aminonaphthalene than bare glassy carbon and multiwalled carbon nanotube–glassy carbon electrodes with a linear dynamic range of 15.0–500.0 nM and a detection limit of 4.5 nM. The modified hybrid electrode was successfully applied for the determination of 2-aminonaphthalene in water.

Electrochemical sensing of 4-nitrochlorobenzene based on carbon nanohorns/graphene oxide nanohybrids

Owing to the harmful nature of 4-nitrochlorobenzene (4-NCB, one toxic organic pollutant) and the low cost, high sensitivity and ease of operation of electrochemical method, it is highly desirable to develop effect electrochemical sensor for the detection of 4-NCB. Herein, by partially unzipping carbon nanohorns (CNHs) via a simple wet-chemistry method, CNHs and graphene oxide (GO) (CNHs/GO) nanohybrids were produced for sensing 4-NCB with synergistic properties. While the retained CNHs offer a path for rapid electron transport, the GO sheets formed by partially unzipping CNHs provide abundant active sites, further increase in surface area as well as improved dispersibility of the CNHs/GO. Our results show that the CNHs/GO modified electrode has excellent sensitivity to 4-NCB with a wide linear response range and a detection limit as low as 10 nM.

Highly efficient detection of salbutamol in environmental water samples by an enzyme immunoassay

Salbutamol (SAL) has potential hazardous effects on health, and has been found in natural water globally. To protect consumers from risks related to SAL residues, a fast and highly sensitive enzyme-linked immunosorbent assay (ELISA) was developed for the detection of SAL in environmental water samples. SAL hapten was synthesized and conjugated to proteins to be used as the immunogen for producing polyclonal antibodies. Under optimized conditions, the ELISA showed a 50% inhibitory concentration (IC50 value) of 0.466μg/L, with a limit of detection (LOD, IC10 value) of 0.021μg/L. The LOD of the ELISA was 5-fold lower than the maximum residue limits. The average recoveries of SAL from environmental samples, including tap water, river water and wastewater, ranged from 80.1 to 115.6%, which is well within the requirements of residue detection. Moreover, the results of the ELISA correlated well with high-performance liquid chromatography results, with a correlation coefficient of 0.988. These results suggest that the proposed ELISA method has potential application for the monitoring of SAL residues in environmental water samples.

Electrochemical sensing for 1-chloro-4-nitrobenzene based on β-cyclodextrin/carbon nanohorns nanohybrids

The occurrence of 1-chloro-4-nitrobenzene (CNB) in the environment due to increased agricultural and economic activities worldwide has been a serious concern for various environmental agencies; hence the qualitative and quantitative determination of CNB is of great significance. In this study, we took into consideration the features of carbon nanohorns (CNHs), such as high surface area and electron transfer ability, and β-cyclodextrin (β-CD), such as high host–guest recognition ability with a hydrophilic outer layer, to design a highly sensitive electrochemical sensor for detecting CNB by preparing CNHs and β-CD nanohybrids through a simple ultrasonication process. The outcome of our study revealed that the CNHs/β-CD nanohybrid modified electrode is an excellent electrochemical sensor for CNB. Under the optimized conditions, the experimental results show a considerable linear response range, unsubstantial interference from familiar organic and inorganic compounds and a detection limit of 9.0 nM.