Meng Jiang,Lin Zhu,Zejun Zhang,Yijing Ai,Lina Zeng,Shuhai He,Lin Li,Wei Sun
In this article the ZIF-8 based metal-organic frameworks-derived porous carbon was mixed with aminated graphene to obtain the nanocomposite, which was used to modify the surface of glassy carbon electrode (GCE). SEM, XRD and FT-IR were used to characterize the nanocomposite, which exhibited the unique morphology with functional groups. The modified electrode was applied to the electrochemical detection of rutin. Compared with that of GCE, the current response of rutin increased obviously on the modified electrode. Square wave voltammetry was further applied to quantitative analysis of rutin with a linear relationship between the concentration and peak current in two sections from 0.25 to 0.7 μmol·L -1 and 0.7 to 1.5 μmol·L -1 with detection limit of 15 nmol∙L -1 . Consequently, the detection of real samples was realized by this method.
In this work, the ferric cobalt sulfide/aminated graphene quantum dots (FeCo 2 S 4 /NH 2 -GQDs) nanoflowers grown on Ni foam substrate have been successfully fabricated via a facile two-step hydrothermal method. The as-prepared FeCo 2 S 4 /NH 2 -GQDs nanoflowers can expose plenty of electroactive sites, provide fast charge transfer paths and buffer the drastic volume change during long-term charge–discharge cycles. Therefore, the FeCo 2 S 4 /NH 2 -GQDs nanoflowers exhibit excellent supercapacitive performance, including high specific capacitance, excellent rate capability and cycling stability. The specific capacitance of FeCo 2 S 4 /NH 2 -GQDs composite electrode reaches 2314.8 and 1802.5 F g −1 at the current density of 1 and 10 A g −1 , respectively, while maintaining superior cycling stability with 95.1% capacitance retention after 5000 cycles. This study proves that NH 2 -GQDs are promising materials to enhance the electrochemical performance of bimetallic sulfides, providing a new insight for the design and fabrication of novel electrode materials for high-performance supercapacitors.
Sensitive electrochemiluminescence (ECL) detection and solid phase microextraction (SPME) using a NH2–graphene–Nafion modified glassy carbon electrode was developed for carbaryl. The NH2–graphene was synthesised and characterised by Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction. The main parameters that affect the extraction efficiencies, such as the buffer and sample pH, and extraction time were investigated and optimised. The introduction of NH2–graphene into Nafion improves the conductivity of the film because of its electrical conductivity. The electrode enables the determination of carbaryl in the range from 5 × 10–4 to 10 μg mL–1, and the limit of detection was 2 × 10–4 μg mL–1 at a signal-to-noise ratio of 3. The ECL intensity retained 97 % of its initial response current after storage for 10 days, indicating a good storage stability of the sensor. The relative standard deviations (RSDs) of intra-assay and inter-assay were found to be 3.5 and 5.3 %, respectively, indicating an acceptable reproducibility. Furthermore, the ECL sensor was successfully applied to the selective and sensitive quantitative determination of carbaryl in river samples, the recoveries of carbaryl ranged from 99.0 to 108.0 %, and the RSDs were less than 5.0 %, which shows good reproducibility and high precision of analysis.
Liu Zixuan,Yin Zheng-Zhi,Cai Wenrong,Wu Datong,Li Junyao,Kong Yong
A surface protein-imprinted biosensor was constructed on a screen-printed carbon electrode (SPCE) for the detection of anti-human immunoglobulin G (anti-IgG). The SPCE was successively decorated with aminated graphene (NH 2 -G) and gold nanobipyramids (AuNBs) for signal amplification. Then 4-mercaptophenylboric acid (4-MPBA) was covalently anchored to the surface of AuNBs for capturing anti-IgG template through boronate affinity binding. The decorated SPCE was then deposited with an imprinting layer generated by the electropolymerization of pyrrole. After removal of the anti-IgG template by the dissociation of the boronate ester in an acidic solution, three-dimensional (3D) cavities complementary to the anti-IgG template were formed in the imprinting layer of polypyrrole (PPy). The molecularly imprinted polymers (MIP)-based biosensor was used for the detection of anti-IgG, exhibiting a wide linear range from 0.05 to 100 ng mL −1 and a low limit of detection of 0.017 ng mL −1 (S/N = 3). In addition, the MIP-based anti-IgG biosensor also shows high selectivity, reproducibility and stability. Finally, the practicability of the fabricated anti-IgG biosensor was demonstrated by accurate determination of anti-IgG in serum sample.
危险品化学品经营许可证（带存储）