ANALYTICAL CHEMISTRY
·
2015
·
IF 5.636
Juan Wei,Zheng Guo,Xing Chen,Dong-Dong Han,Xiang-Ke Wang,Xing-Jiu Huang
Detection of Cr(VI) by electrochemical methods generally focuses on noble-metal-modified electrodes in strong acid solution using voltammetric techniques. In this work, we report a new strategy to detect Cr(VI) as HCrO4– at pH 5.0 in drinking water using electrochemical impedance spectroscopy. The strategy is based on the high-affinity and specific binding of crown ethers (i.e., azacrown) to HCrO4–, which forms sandwich complexes between them via hydrogen bonds and moiety interactions with K+ captured by azacrown on its self-assembled Au electrode surface. This then blocks the access of redox probes (Fe(CN)63–/4–) to the self-assembled Au electrode, further resulting in an increase in the electron transfer resistance. This method offers a detection limit of 0.0014 ppb Cr(VI) with a sensitivity of 4575.28 kΩ [log c (ppb)]−1 over the linear range of 1–100 ppb (R2 = 0.994) at pH 5.0. In addition, the azacrown self-assembled Au electrode has good selectivity for Cr(VI) with good stability and low interferences. This approach can be performed on spiked Cr(VI) as well as real samples. To the best of our knowledge, this is the first example of electrochemical impedimetric sensing that allows ultrasensitive and ultraselective detection of Cr(VI).
研究领域:
分析化学
·
环境科学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2025
·
IF 4.1
Hu Fu,Weigang Zhu,Wenhua Xu,Zhongwei Zhao
Lithium-ion detection is necessary for extraction of lithium. Electrochemical sensors based on spinel LiMn 2 O 4 /λ-MnO 2 are expected to enable low-cost detection of lithium ions. Many studies demonstrate preferential intercalation of lithium ions, but little research has been done on how the differences in intercalation between lithium and other ions arise. Here, the differences in intercalation were identified by electrochemical impedance spectroscopy. Lithium ions were preferentially intercalated into λ-MnO 2 because of low charge transfer impedance. The apparent diffusion coefficient of sodium or potassium ions was one order of magnitude lower than that of lithium ions, while that of magnesium or calcium ions was two orders of magnitude lower. Therefore, insignificant intercalation of sodium, magnesium, potassium, and calcium ions slowed down diffusion of lithium ions through the channel and obstructed lithium-ion intercalation. The concentration of lithium ions was detected in brine of Baqiancuo Salt Lake by stripping voltammetry using λ-MnO 2 and an average recovery of 95.0 % was achieved. This study gives insights into ion intercalation of LiMn 2 O 4 in brine, which favors improvement of lithium-ion sensor based on LiMn 2 O 4 . In addition, the investigation facilitates understanding of the selectivity of similar materials (e.g., LiFePO 4 and Prussian blue analogous) in intercalation process.
研究领域:
材料科学
·
电化学传感器
✓ 已验证
产品关联
DOI
高影响因子
JOM
·
2019
·Vol. 72
·期 12
·4288-4295
·
IF 2.305
Zhang Jia-Wei,Li Ying,Ding Yu-Shi,Pan Ke-Feng,Zhao Qing
Poly( o -phenylenediamine) was synthesized in different inorganic acid media, hydrochloric (HCl), nitric (HNO 3 ), and phosphoric acid (H 3 PO 4 ).
The aim was to investigate the protective effect of doped coatings on mild steel in an aggressive environment. The synthesized doped-PoPD products were characterized by x-ray diffractometry, Fourier transform infrared spectroscopy, scanning electron microscopy, and cyclic voltammetry. The inhibition abilities of doped coatings were evaluated by potentiodynamic polarization measurements and electrochemical impedance spectroscopy in 3.5% NaCl solution. In the present article, the lowest corrosion current and highest protection efficiency of the doped polymer were observed for the polymer synthesized in HNO 3 medium. The results showed that good protection of mild steel can be achieved by PoPD coating doped with inorganic acid in 3.5% NaCl solution.
研究领域:
材料科学
·
腐蚀与防护
✓ 已验证
DOI
高影响因子
Materials Today Communications
·
2024
·
IF 3.7
Yiting He,Xin Qi,Zongze Peng,Yunxia Ren,Hongjian Yang,Xiaoli Liu
In this study, halloysite nanotubes (HNTs) were first etched with H 2 SO 4 or NaOH and then loaded with a green corrosion inhibitor (sodium benzoate, SB) under vacuum. Subsequently, a thin layer of tetraethyl orthosilicate (TEOS) was coated for the controlled release of SB. The dispersion of the coated HNTs in epoxy resin was improved by amino functionalization with (3-aminopropyl) triethoxysilane (APTES). The obtained S24HNTs-SB-TEOS-APTES nanocapsules were analyzed by Brunauer-Emmett-Teller (BET), showing that after etching with 5 mol/L of H 2 SO 4 for 24 h, the pore size inside the HNTs increased, and the tubular morphology was maintained. According to the results of UV–visible spectroscopy, SB was released faster in acidic (pH=3) and alkaline conditions (pH=11) than neutral condition. Furthermore, nanocapsules were successfully embedded in epoxy coating used for corrosion protection of carbon steel. The electrochemical impedance spectroscopy (EIS) and salt spray experiments demonstrated that the smart composite coating exhibited outstanding corrosion resistance , and the addition of 3 wt% S24HNTs-SB-TEOS-APTES having the most excellent anticorrosion performance with its impedance at 0.01 Hz maintaining 3.11 × 10 6 Ω⋅cm 2 even after 3 weeks of corrosion immersion.
研究领域:
材料科学
·
腐蚀与防护
·
纳米技术
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2016
·
IF 3.15
Fubao Gong,Jun Shen,Runhua Gao,Xiong Xie,Xiong Luo
A novel organic–inorganic Mg(OH) 2 /silane surface layer has been developed for corrosion protection of AZ31 magnesium alloy. The results of electrochemical impedance spectroscopy (EIS), the immersion tests, Fourier-transform infrared spectroscopy (FTIR) and sellotape tests showed that the Mg(OH) 2 /silane-based composite surface layer possessed excellent corrosion resistance and very good adhesion due to the formation of Si–O–Mg bond between Mg(OH) 2 layer and silane layer. Electrochemical impedance spectroscopy tests results indicated that for the long-term corrosion protection of AZ31 the increase of the curing temperature improved the impedance of the composited layer when the curing temperature was lower than 130 °С. However, the impedance of the composited layer deceased when the curing temperature was more than 130 °С due to the carbonization of the silane layer.
研究领域:
材料科学
·
腐蚀与防护
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2016
·
IF 7.145
Guanghui Li,Min Zhu,Lu Ma,Junrong Yan,Xiaoling Lu,Yanfei Shen,Yakun Wan
A phage display library of variable domain of the heavy chain only antibody or nanobody (Nb) was constructed after immunizing a bactrian camel with testosterone. With the smaller molecular size (15 kDa), improved solubility, good stability, high affinity, specificity, and lower immunogenicity, Nbs are a promising tool in the next generation of diagnosis and medical applications. Testosterone is a reproductive hormone, playing an important role in normal cardiac function and being the highly predictive marker for many diseases. Herein, a simple and sensitive immunosensor based on electrochemical impedance spectroscopy (EIS) and Nbs was successfully developed for the determination of testosterone. We successfully isolated the antitestosterone Nbs from an immune phage display library. Moreover, one of the Nbs was biotinylated according to in vivo BirA system, which showed the highest production yield and the most stable case. Further, the EIS immunosensor was set up for testosterone detection by applying the biotinylated antitestosterone Nb. As a result, the biosensor exhibited a linear working range from 0.05 to 5 ng mL–1 with a detection limit of 0.045 ng mL–1. In addition, the proposed immunosensor was successfully applied in determining testosterone in serum samples. In conclusion, the proposed immunosensor revealed high specificity of testosterone detection and showed as a potential approach for sensitive and accurate diagnosis of testosterone.
研究领域:
生物技术
·
医学诊断
·
分析化学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2018
·
IF 3.794
Hai Jiang,Xiao-Hong Wang,Wen Lei,Gui-Fen Fan,Wen-Zhong Lu
The effects of two-step sintering on the microstructure, mechanical and thermal properties of aluminum nitride ceramics with Yb 2 O 3 and YbF 3 additives were investigated. AlN samples prepared using different sintering methods achieved almost full density with the addition of Yb 2 O 3 –YbF 3 . Compared with the one-step sintering, the grain sizes of AlN ceramics prepared by the two-step sintering were limited, and the higher flexural strength and the larger thermal conductivity were obtained. Moreover, the electrochemical impedance spectroscopy of AlN ceramic was associated with thermal conductivity by analyzing the defects and impurities in AlN ceramics. The fitting grain resistance and the activation energy for the grain revealed the lower concentrations of aluminum vacancy in the two-step sintered AlN ceramics, which resulted in the higher thermal conductivity. Thus, mechanical and thermal properties for AlN ceramics were improved with Yb 2 O 3 and YbF 3 additives sintered using two-step regimes.
研究领域:
材料科学
·
热力学
✓ 已验证
DOI
高影响因子
ChemistrySelect
·
2025
·Vol. 10
·期 13
·e202500754
·
IF 2
Bing Lei,Yao Yao,Taiyuan Zhang,Sifan Tu,Keqi Huang,Jianxiang Cao,Zi Yang,Zhiyuan Feng
Graphical In this work, a direct immersion method was utilized to modify waterborne polyurethane (WPU) coatings with PDA, which introduces a new convenient strategy for enhancing WPU coatings and enriches corrosion protection methods for Al alloys. Al alloys are widely used, primarily due to their excellent electrical conductivity, thermal conductivity, formability, and weldability. However, corrosion issues have limited their further development. Organic coatings are an important means of corrosion protection, yet as environmental awareness grows, waterborne anticorrosion coatings (e.g., waterborne polyurethanes) are gradually replacing traditional organic coatings. Compared with solvent-based organic coatings, however, waterborne coatings still face shortcomings in their protective performance and require modification. This study used polydopamine (PDA) to modify a waterborne polyurethane (WPU) coating. Samples were immersed in a 3.5 wt.% NaCl solution, and the properties of the coatings before and after modification were evaluated by electrochemical impedance spectroscopy (EIS). After 30 days of immersion in 3.5 wt.% NaCl, the maximum |Z| 0.01 Hz of PDA-modified WPU was more than 8.0 × 10 5 Ω∙cm 2 , which is significantly higher than the |Z| 0.01 Hz of 1.0 × 10 5 Ω∙cm 2 for the unmodified WPU. Various characterization techniques demonstrated that PDA successfully addressed defects in the WPU coating, improving its overall density. This densification effectively slowed the diffusion of chloride ions and other corrosive species, thereby enhancing the coating's anti-corrosion performance. This work introduces a new strategy for enhancing waterborne polyurethane coatings and enriches corrosion protection methods for aluminum alloys.
研究领域:
材料科学
·
腐蚀与防护
·
表面工程
✓ 已验证
产品关联
DOI
高影响因子
DIAMOND AND RELATED MATERIALS
·
2024
·
IF 4.3
Yihe Peng,Baoli Ou,Yongjie Peng,Tianyu Cheng,Mieyi Wen,Huan Liu
In order to enhance the corrosion resistance of epoxy resin (EP) coating system, we put forward a facile approach to prepare hydrophobic fluorinated graphene (FG) filler for the EP coating by one-pot hydrothermal reaction in this work. Fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), contact angle measuring instrument and scanning electron microscopy (SEM) were employed for the FG characterization. The SEM images of fracture morphology revealed that FG uniformly dispersed in epoxy resin matrix. Additionally, the excellent water resistance and the lower coefficient of friction of FG/EP coating was confirmed through the water absorption test and friction and wear test machine. The electrochemical impedance spectroscopy (EIS) demonstrated that the impedance value at the low frequency (|Z| 0.01Hz ) of 0.50 wt% FG/EP was 3.49 × 10 7 Ω·cm 2 after being immersed in 3.5 wt% NaCl solution for 60 days, which was about 2 orders of magnitude higher than that of the pure EP coating (4.74 × 10 5 Ω·cm 2 ). The 0.50 wt% FG/EP coating exhibited the superior anti-corrosion performance due to the FG with the two-dimensional sheet structure, uniform dispersion and hydrophobicity properties.
研究领域:
材料科学
·
腐蚀与防护
✓ 已验证
产品关联
DOI
高影响因子
MOLECULES
·
2022
·Vol. 27
·期 3
·615
·
IF 4.927
Yunxiao Feng,Gang Liu,Ming La,Lin Liu
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) main protease (Mpro) has been regarded as one of the ideal targets for the development of antiviral drugs. The currently used methods for the probing of Mpro activity and the screening of its inhibitors require the use of a double-labeled peptide substrate. In this work, we suggested that the label-free peptide substrate could induce the aggregation of AuNPs through the electrostatic interactions, and the cleavage of the peptide by the Mpro inhibited the aggregation of AuNPs. This fact allowed for the visual analysis of Mpro activity by observing the color change of the AuNPs suspension. Furthermore, the co-assembly of AuNPs and peptide was achieved on the peptide-covered electrode surface. Cleavage of the peptide substrate by the Mpro limited the formation of AuNPs/peptide assembles, thus allowing for the development of a simple and sensitive electrochemical method for Mpro detection in serum samples. The change of the electrochemical signal was easily monitored by electrochemical impedance spectroscopy (EIS). The detection limits of the colorimetric and electrochemical methods are 10 and 0.1 pM, respectively. This work should be valuable for the development of effective antiviral drugs and the design of novel optical and electrical biosensors.Keywords:SARS-CoV-2 main protease;colorimetry;electrochemical impedance spectroscopy;gold nanoparticles
研究领域:
病毒学
·
分析化学
·
生物医学工程
✓ 已验证
DOI
PubMed
高影响因子
SURFACE ENGINEERING
·
2020
·
IF 2.433
Hongchao Wang,Shicheng Wang,Yiyi Li,Meng Li,Yiting Xu,Kaibin He,Conghui Yuan,Birong Zeng,Lizong Dai
Polyaniline/graphene oxide (GON-An) composites were synthesized by chemically grafting p-phenylenediamine (PPDA)-modified graphene oxide (GO) with polyaniline (PANI), which was confirmed by FT-IR, XRD, SEM, TEM, Raman spectroscopy, and XPS analyses. The electrochemical impedance spectroscopy test, brine immersion, and Tafel slopes analysis revealed that compared with GO and PPDA-modified GO (GON), GON-An composites which combined the unique corrosion resistance of both PANI and GO exhibited relatively obvious superiority in improving the corrosion resistance of epoxy coating with the same contents. After being immersed in brine for 35 days, the composite epoxy coating containing 1 wt-% of GON-An(1:2) composites in which the mass ratio of GO and PANI was 1:2, possessed a high impedance of 4×109 Ω cm2, a high corrosion potential of −0.25 V, and a low corrosion current of 4.119×10−11 A cm−2. Furthermore, the anti-corrosive mechanisms of PANI/GO epoxy coatings were discussed.
研究领域:
材料科学
·
腐蚀与防护
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Nano Materials
·
2018
·
IF 0
Lu Shen,Yong Li,Wenjie Zhao,Lijing Miao,Weiping Xie,Huanming Lu,Kui Wang
In order to hold the excellent corrosion resistance of zinc-rich epoxy coatings with reduced zinc content, five types of graphene modified zinc-rich epoxy coatings (G-ZRCs) were prepared. The effect of zinc content on the corrosion protection behaviors of G-ZRCs was investigated using electrochemical impedance spectroscopy (EIS). Open circuit potential (OCP) was also utilized to deepen the understanding of the anticorrosion mechanism of the as-prepared composite coatings. The results confirmed that addition of 0.3 wt % graphene could make the coating with 40 wt % (G-40ZRC) and 55 wt % zinc (G-55ZRC) provide cathodic protection for a short period of time. The EIS and OCP results showed a dominant physical barrier protection mechanism for the coatings without zinc (G-ZRC), while there was a mixed mechanism for G-40ZRC and G-55ZRC and a dominant cathodic protection mechanism for the coatings with 70 and 85 wt % zinc (G-70ZRC and G-85ZRC). Furthermore, the graphene modified zinc-rich coatings and corresponding corrosion products immersed in a 3.5% NaCl solution for 100 days were also characterized, which could further reveal anticorrosion mechanisms of the graphene modified zinc-rich coatings and the passivation effect of polyaniline (PANI).
研究领域:
材料科学
·
腐蚀与防护
✓ 已验证
产品关联
DOI
危险品化学品经营许可证（带存储）