scholarly journals Reusability of SPE and Sb-modified SPE Sensors for Trace Pb(II) Determination

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3976 ◽  
Author(s):  
Matjaž Finšgar ◽  
David Majer ◽  
Uroš Maver ◽  
Tina Maver
Keyword(s):  
Electrochemical Impedance ◽  
Standard Addition ◽  
Linear Calibration ◽  
Surface Characterisation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Before And After ◽  
Sensor Degradation ◽  
First Time

In this work, unmodified screen-printed electrode (bare SPE) and Sb-film modified SPE (SbFSPE) sensors were employed for the analysis of trace amounts of Pb(II) in non-deaerated water solutions. The modified electrode was performed in situ in 0.5 mg/L Sb(III) and 0.01 M HCl. The methodology was validated for an accumulation potential of –1.1 V vs. Ag/AgCl and an accumulation time of 60 s. A comparative analysis of bare SPE and SbFSPE showed that the detection and quantification limits decrease for the bare SPE. The method with the bare SPE showed a linear response in the 69.8–368.4 µg/L concentration range, whereas linearity for the SbFSPE was in the 24.0–319.1 µg/L concentration range. This work also reports the reason why the multiple standard addition method instead of a linear calibration curve for Pb(II) analysis should be employed. Furthermore, the analytical method employing SbFSPE was found to be more accurate and precise compared to the use of bare SPE when sensors were employed for the first time, however this performance changed significantly when these sensors were reused in the same manner. Furthermore, electrochemical impedance spectroscopy was used for the first time to analyse the electrochemical response of sensors after being used for multiple successive analyses. Surface characterisation before and after multiple successive uses of bare SPE and SbFSPE sensors, with atomic force microscopy and field emission scanning electron microscopy, showed sensor degradation. The interference effect of Cd(II), Zn(II), As(III), Fe(II), Na(I), K(I), Ca(II), Mg(II), NO3–, Bi(III), Cu(II), Sn(II), and Hg(II) on the Pb(II) stripping signal was also studied. Finally, the application of SbFSPE was tested on a real water sample (from a local river), which showed high precision (RSD = 8.1%, n = 5) and accurate results.

scholarly journals Reusability of SPE and Sb-Mmodified SPE Sensors for Trace Pb(II) Determination

2018 ◽  
Author(s):  
Matjaž Finšgar ◽  
David Majer ◽  
Uroš Maver ◽  
Tina Maver
Keyword(s):  
Electrochemical Impedance ◽  
Standard Addition ◽  
Linear Calibration ◽  
Surface Characterisation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Before And After ◽  
Sensor Degradation ◽  
First Time

In this work, unmodified screen-printed electrode (bare SPE) and Sb-film modified SPE (SbFSPE) sensors were employed for the analysis of trace amounts of Pb(II) in non-deaerated water solutions. The modified electrode was performed in situ in 0.5 mg/L Sb(III) and 0.01 M HCl. The methodology was validated for an accumulation potential of –1.1 V vs. Ag/AgCl and an accumulation time of 60 s. A comparative analysis of bare SPE and SbFSPE showed that the detection and quantification limits decrease for the bare SPE. The method with the bare SPE showed a linear response in the 69.8–368.4 µg/L concentration range, whereas linearity for the SbFSPE was in the 24.0–319.1 µg/L concentration range. This work also reports the reason why the multiple standard addition method instead of a linear calibration curve for Pb(II) analysis should be employed. Furthermore, the analytical method employing SbFSPE was found to be more accurate and precise compared to the use of bare SPE when sensors were employed for the first time, however this performance changed significantly when these sensors were reused in the same manner. Furthermore, electrochemical impedance spectroscopy was used for the first time to analyse the electrochemical response of sensors after being used for multiple successive analyses. Surface characterisation before and after multiple successive uses of bare SPE and SbFSPE sensors, with atomic force microscopy and field emission scanning electron microscopy, showed sensor degradation. The interference effect of Cd(II), Zn(II), As(III), Fe(II), Na(I), K(I), Ca(II), Mg(II), NO3– Bi(III), Cu(II), Sn(II), and Hg(II) on the Pb(II) stripping signal was also studied. Finally, the application of SbFSPE was tested on a real water sample (from a local river), which showed high precision (RSD = 8.1%, n = 5) and accurate results.

scholarly journals Experimental and Theoretical Study of the Covalent Grafting of Triazole Layer onto the Gold Surface

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2927
Author(s):  
Nimet Orqusha ◽  
Sereilakhena Phal ◽  
Avni Berisha ◽  
Solomon Tesfalidet
Keyword(s):  
Photoelectron Spectroscopy ◽  
Density Functional ◽  
Electrochemical Impedance ◽  
Gold Surface ◽  
Covalent Attachment ◽  
Force Microscopy ◽  
Atomic Force ◽  
Covalent Grafting ◽  
Before And After

Finding novel strategies for surface modification is of great interest in electrochemistry and material sciences. In this study, we present a strategy for modification of a gold electrode through covalent attachment of triazole (TA) groups. Triazole groups were electrochemically grafted at the surface of the electrode by a reduction of in situ generated triazolediazonium cations. The resulting grafted surface was characterized before and after the functionalization process by different electrochemical methods (cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS)) confirming the presence of the grafted layer. The grafting of TA on the electrode surface was confirmed using analysis of surface morphology (by atomic force microscopy), the thickness of the grafted layer (by ellipsometry) and its composition (by X-ray photoelectron spectroscopy). Density functional theory (DFT) calculations imply that the grafted triazole offers a stronger platform than the grafted aryl layers.

Corrosion Behaviors Studied in Self-Assembled Processes of Alkanethiol Monolayers on Polycrystalline Gold Substrates

2007 ◽  
Vol 121-123 ◽  
pp. 385-388
Author(s):  
Z. Cao ◽  
Zhong Liang Xiao ◽  
Ning Gu ◽  
S. Shimada ◽  
T. Fukuda ◽  
...  
Keyword(s):  
Corrosion Rate ◽  
Quartz Crystal ◽  
Force Microscopy ◽  
Atomic Force ◽  
Gold Substrates ◽  
Corrosion Behaviors ◽  
Polycrystalline Gold ◽  
First Time ◽  
Fast Stage

In this paper, the corrosion phenomenon occurred on the polycrystalline gold substrates has been for the first time observed by in situ quartz crystal microbalance (QCM) method for adsorption of alkanethiol monolayers, which may be attributed to thiol-induced dissolution of gold during the adsorption process in the presence of oxygen. It is evident from the image of many corrosive defects or holes produced on the surface of gold grains by using atomic force microscopy (AFM). The kinetic equation on corrosion rate of gold dissolved in the organothiol solution has been obtained. The gold corrosion rate at fast stage can be estimated to be 9.2 × 1011 Au atoms cm-2 s-1.

Alumina-Silicate Glass Interfacial Properties Probed by Micromechanical Testing Techniques

1995 ◽  
Vol 401 ◽  
Author(s):  
Andrey V. Zagrebelnya ◽  
John C. Nelson ◽  
Erica T. Lilleodden ◽  
Sundar Ramamurthy ◽  
C. Barry Carter
Keyword(s):  
Force Microscopy ◽  
Operating Modes ◽  
Deformation Structures ◽  
Atomic Force ◽  
Afm Imaging ◽  
Before And After ◽  
Calcium Aluminosilicate ◽  
Testing Techniques ◽  
Force Displacement

AbstractMicromechanical properties of the interfaces between alumina and calcium-aluminosilicate (CAS) glasses were tested using various micro/nanoindentation techniques. The interfaces were produced by depositing continuous films of anorhtite (CaAl2Si2O8) onto single-crstal α-Al2O3 of two crystallographic orientations by pulsed-laser deposition (PLD).The mechanical behavior of the interfaces was examined using two different depthsensing indentation instruments. Three types of tests, namely indentation, microscratch, and in-situ indentation combined with atomic force microscopy (AFM) imaging were conducted using different operating modes. The deformation behavior observed for the indentations and microscratches has been correlated with irregularities observed in the load-displacement curves. In the first two cases, scanning electron microscopy (SEM) has been used to characterize the deformation structures associated with the deformed regions. The in-situ experiments allow force-displacement measurements and AFM imaging immediately before and after indentation. The preindent and postindent morphology of the surface could then be characterized.

scholarly journals Surface Characterization of Absorbing Polymer Films Deposited on Transparent Glasses

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Débora Gonçalves ◽  
Silmar A. Travain ◽  
José A. Giacometti ◽  
Eugene A. Irene
Keyword(s):  
Polymer Films ◽  
Surface Characterization ◽  
Transparent Glass ◽  
Force Microscopy ◽  
Glass Substrates ◽  
Atomic Force ◽  
Vis Spectroscopy ◽  
Before And After

AbstractPANI films were deposited on glass substrates by in-situ polymerization and characterized by UV-VIS spectroscopy and atomic force microscopy. A method is developed to accurately analyze ellipsometric data obtained for transparent glass substrates before and after modification with absorbing polymer films. Surface modification was made with an overlayer such as polyaniline (PANI), which exhibits different optical properties by varying its oxidation state. First, the issue of using transparent substrates for ellipsometry studies was examined and then, spectroscopic ellipsometry was used to characterize absorbing overlayers on transparent glasses. The same methodologies of data analysis can be also applied to other absorbing films on transparent substrates, and deposited by different techniques

scholarly journals In situ AFM visualization of Li–O2 battery discharge products during redox cycling in an atmospherically controlled sample cell

2019 ◽  
Vol 10 ◽  
pp. 930-940 ◽  
Author(s):  
Kumar Virwani ◽  
Younes Ansari ◽  
Khanh Nguyen ◽  
Francisco José Alía Moreno-Ortiz ◽  
Jangwoo Kim ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Double Layers ◽  
In Situ Observation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Highly Sensitive ◽  
Wide Range ◽  
Battery Discharge ◽  
The Impact

The in situ observation of electrochemical reactions is challenging due to a constantly changing electrode surface under highly sensitive conditions. This study reports the development of an in situ atomic force microscopy (AFM) technique for electrochemical systems, including the design, fabrication, and successful performance of a sealed AFM cell operating in a controlled atmosphere. Documentation of reversible physical processes on the cathode surface was performed on the example of a highly reactive lithium–oxygen battery system at different water concentrations in the solvent. The AFM data collected during the discharge–recharge cycles correlated well with the simultaneously recorded electrochemical data. We were able to capture the formation of discharge products from correlated electrical and topographical channels and measure the impact of the presence of water. The cell design permitted acquisition of electrochemical impedance spectroscopy, contributing information about electrical double layers under the system’s controlled environment. This characterization method can be applied to a wide range of reactive surfaces undergoing transformations under carefully controlled conditions.

scholarly journals Time‐resolved in situ electrochemical atomic force microscopy imaging of the corrosion dynamics of AA2024‐T3 using a new design of cell

2021 ◽  
Author(s):  
Ahmed Kreta ◽  
Miran Gaberšček ◽  
Igor Muševič
Keyword(s):  
Atomic Force Microscopy ◽  
Electrochemical Cell ◽  
Electrochemical Impedance ◽  
Electrical Field ◽  
Microscopy Imaging ◽  
Time Resolved ◽  
Simultaneous Application ◽  
Force Microscopy ◽  
Atomic Force

AbstractAn electrochemical cell was designed to enable in situ atomic force microscopy (AFM) measurements. The finite‐element method was implemented using COMSOL Multiphysics to simulate the electrical field within the cell and to find the current and potential distribution. A comparative three‐dimensional simulation study was made to compare two different designs and to elucidate the importance of the geometry on the electrical field distribution. The design was optimized to reduce the uncertainty in the measurement of the electrochemical impedance. Then, an in situ, simultaneous electrochemical and time‐resolved AFM experiments were conducted to study the surface evolution of the aluminum alloy AA2024‐T3 exposed to 0.5 M NaCl. The temporal change of the surface topography was recorded during the application of chrono‐amperometric pulses using a newly designed electrochemical cell. Electrochemical impedance spectroscopy was conducted on the sample to confirm the recorded topographical change. The newly developed cell made it possible to monitor the surface change and the growth of the oxyhydroxide layer on the AA2024‐T3 with the simultaneous application of electrochemical methods.

Corrosion and mechanical behavior evaluation of in-situ synthesized Cu-TiB2 nanocomposite

2021 ◽  
Vol 1 (2) ◽  
pp. 121-126
Author(s):  
Hossein Aghajani ◽  
Seyed Ali Naziri Mehrabani ◽  
Arvin Taghizadeh Tabrizi ◽  
Falih Hussein Saddam
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Copper Matrix ◽  
Polarization Current ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Galvanic Couples ◽  
Matrix Nanocomposite

In this paper, the synthesis of the copper matrix nanocomposite and the effect of adding TiB2 nanoparticles on the copper matrix was investigated. Three different amounts of TiB2 nanoparticles 5, 10, and 15 wt% were added and sintering was carried out at 900 oC for 4 hours under argon atmosphere. The phase formation of achieved nanocomposites was studied by X-ray diffractometer and the morphology of the synthesized samples was studied by field emission scanning electron microscopy and atomic force microscopy. The polarization and electrochemical impedance spectroscopy (EIS) at 3.5 wt% NaCl solution at room temperature was were carried out to evaluate the corrosion behavior of synthesized samples. Results show that adding the TiB2 nanoparticles decrease the corrosion resistance by the formation of galvanic couples, but the effect of amounts of porosities on the corrosion resistance is higher. It is revealed that the variation of the surface roughness is in direct relation to the value of polarization current density.

Surface roughness measurements of vanadium-contaminated fluidized cracking catalysts by atomic force microscopy

1996 ◽  
Vol 54 ◽  
pp. 866-867
Author(s):  
H. Kinney ◽  
M.L. Occelli ◽  
S.A.C. Gould
Keyword(s):  
Surface Roughness ◽  
Zeolite Y ◽  
Atomic Level ◽  
Microporous Structure ◽  
Contact Mode ◽  
Force Microscopy ◽  
Atomic Force ◽  
Before And After ◽  
Roughness Measurements ◽  
Cracking Catalysts

For this study we have used a contact mode atomic force microscope (AFM) to study to topography of fluidized cracking catalysts (FCC), before and after contamination with 5% vanadium. We selected the AFM because of its ability to well characterize the surface roughness of materials down to the atomic level. It is believed that the cracking in the FCCs occurs mainly on the catalysts top 10-15 μm suggesting that the surface corrugation could play a key role in the FCCs microactivity properties. To test this hypothesis, we chose vanadium as a contaminate because this metal is capable of irreversibly destroying the FCC crystallinity as well as it microporous structure. In addition, we wanted to examine the extent to which steaming affects the vanadium contaminated FCC. Using the AFM, we measured the surface roughness of FCCs, before and after contamination and after steaming.We obtained our FCC (GRZ-1) from Davison. The FCC is generated so that it contains and estimated 35% rare earth exchaged zeolite Y, 50% kaolin and 15% binder.

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