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Margaret K. Joyce - One of the best experts on this subject based on the ideXlab platform.

  • Detection of Heavy Metal Compounds using a novel inkjet printed surface enhanced Raman spectroscopy (SERS) substrate
    Sensors and Actuators B-chemical, 2012
    Co-Authors: Ali Eshkeiti, Binu B. Narakathu, A. S. G. Reddy, Massood Z. Atashbar, A. Moorthi, E. Rebrosova, Marian Rebros, Margaret K. Joyce
    Abstract:

    Abstract A novel surface enhanced Raman spectroscopy (SERS) substrate was successfully fabricated on a silicon wafer using inkjet printing. Silver (Ag) nanoparticle (NP) based ink, with average particle size of 150 nm, was inkjet printed on the surface of the silicon wafer. A thickness of 400 nm was measured for the printed Ag NP film using vertical scanning interferometry. The Ag NP printed SERS substrate was tested toward Heavy Metal Compounds like cadmium sulfide (CdS), zinc oxide (ZnO) and mercury sulfide (HgS). An amplification of the SERS intensity by an order of 3–5 times was observed for all test samples, due to the presence of hotspots between the Metal nanoparticle aggregates. The responses demonstrated the feasibility of the novel SERS substrate to be used in applications for detection of Heavy Metal Compounds.

  • Gravure printed surface enhanced Raman spectroscopy (SERS) substrates for detection of toxic Heavy Metal Compounds
    SENSORS 2012 IEEE, 2012
    Co-Authors: A. Eshkeiti, A. S. G. Reddy, Margaret K. Joyce, B. B. Narakathu, B. J. Bazuin, M. Z. Atashbar
    Abstract:

    A novel flexible surface enhanced Raman spectroscopy (SERS) substrate was successfully fabricated by gravure printing a silver (Ag) nanoparticle ink, with a particle size of ~20-50 nm particle size, as a Metallization layer on a flexible polyethylene terephthalate film (PET). The capability of the fabricated SERS substrate to be used as a sensor for detecting toxic Heavy Metal Compounds, such as mercury sulfide (HgS) was demonstrated. An enhancement factor of 5 orders of magnitude was obtained when compared to the intensity of a Raman spectrum of for target molecules adsorbed onto bare PET. Theis response obtained demonstrated the feasibility of thise novel SERS substrate to be used in applications for the detection of toxic Heavy Metals. In addition, the effect of temperature on the intensity of the Raman spectrum was also tested. The results showed an 85 % decrease in intensity at 85 °C, when compared with the intensity of te Raman sprectrum at 25 °C.

A. S. G. Reddy - One of the best experts on this subject based on the ideXlab platform.

  • SH-SAW sensor based microfluidic system for the detection of Heavy Metal Compounds in liquid environments
    Sensors and Actuators B: Chemical, 2015
    Co-Authors: Zeinab Ramshani, Binu B. Narakathu, A. S. G. Reddy, Jared T. Wabeke, Sherine O. Obare, Massood Z. Atashbar
    Abstract:

    Abstract In this work, a guided shear horizontal mode surface acoustic wave (SH-SAW) sensor, fabricated by patterning gold (Au) interdigitated electrodes (IDE) on a 64° YX-LiNbO3 based piezoelectric substrate, was used for the detection of Heavy Metal Compounds. A flow cell, with a reservoir volume of 3 μL, which employs inlet and outlet valves for the microfluidic chamber and polydimethylsiloxane (PDMS) based microfluidic channels, was also designed and fabricated using an acrylic material. The frequency based response of the SAW sensor toward varying concentrations of Heavy Metal Compounds such as lead nitrate (PbNO3) and cadmium nitrate (CdNO3) were investigated. As the surface acoustic wave propagates on the substrate, between input and output IDEs, a shift in the resonant frequency of the SAW device was observed due to the change in velocity of the wave caused by the varying concentrations of the test analytes. The results obtained demonstrated the capability of the system to detect picomolar level concentrations. The response of the SAW sensor is analyzed and presented in this paper.

  • Opto-electrochemical based dual detection of Heavy Metal Compounds using a novel flow cell
    2013 IEEE SENSORS, 2013
    Co-Authors: Binu B. Narakathu, A. S. G. Reddy, Ali Eshkeiti, Bradley J. Bazuin, Massood Z. Atashbar
    Abstract:

    An efficient sensing system that detects Heavy Metal Compounds, by employing opto-electrochemical based dual detection technique, has been successfully developed. A novel microfluidic flow cell consisting of an inlet and outlet port with a reservoir volume of 25 μl was designed and fabricated using acrylic material. An electrochemical sensor with gold (Au) interdigitated electrodes (IDE) on a glass substrate was used for the electrical impedance spectroscopy (EIS) of various Heavy Metal Compounds. EIS performed on cadmium sulfide (CdS) and mercury sulfide (HgS) yielded picomolar (pM) concentration detection levels. Selective detection of Heavy Metal Compounds was made possible based on optical signals produced in the Raman emission spectra. The response of this dual detection sensing system is analyzed and presented in this paper.

  • Detection of Heavy Metal Compounds using a novel inkjet printed surface enhanced Raman spectroscopy (SERS) substrate
    Sensors and Actuators B-chemical, 2012
    Co-Authors: Ali Eshkeiti, Binu B. Narakathu, A. S. G. Reddy, Massood Z. Atashbar, A. Moorthi, E. Rebrosova, Marian Rebros, Margaret K. Joyce
    Abstract:

    Abstract A novel surface enhanced Raman spectroscopy (SERS) substrate was successfully fabricated on a silicon wafer using inkjet printing. Silver (Ag) nanoparticle (NP) based ink, with average particle size of 150 nm, was inkjet printed on the surface of the silicon wafer. A thickness of 400 nm was measured for the printed Ag NP film using vertical scanning interferometry. The Ag NP printed SERS substrate was tested toward Heavy Metal Compounds like cadmium sulfide (CdS), zinc oxide (ZnO) and mercury sulfide (HgS). An amplification of the SERS intensity by an order of 3–5 times was observed for all test samples, due to the presence of hotspots between the Metal nanoparticle aggregates. The responses demonstrated the feasibility of the novel SERS substrate to be used in applications for detection of Heavy Metal Compounds.

  • Gravure printed surface enhanced Raman spectroscopy (SERS) substrates for detection of toxic Heavy Metal Compounds
    SENSORS 2012 IEEE, 2012
    Co-Authors: A. Eshkeiti, A. S. G. Reddy, Margaret K. Joyce, B. B. Narakathu, B. J. Bazuin, M. Z. Atashbar
    Abstract:

    A novel flexible surface enhanced Raman spectroscopy (SERS) substrate was successfully fabricated by gravure printing a silver (Ag) nanoparticle ink, with a particle size of ~20-50 nm particle size, as a Metallization layer on a flexible polyethylene terephthalate film (PET). The capability of the fabricated SERS substrate to be used as a sensor for detecting toxic Heavy Metal Compounds, such as mercury sulfide (HgS) was demonstrated. An enhancement factor of 5 orders of magnitude was obtained when compared to the intensity of a Raman spectrum of for target molecules adsorbed onto bare PET. Theis response obtained demonstrated the feasibility of thise novel SERS substrate to be used in applications for the detection of toxic Heavy Metals. In addition, the effect of temperature on the intensity of the Raman spectrum was also tested. The results showed an 85 % decrease in intensity at 85 °C, when compared with the intensity of te Raman sprectrum at 25 °C.

Massood Z. Atashbar - One of the best experts on this subject based on the ideXlab platform.

  • A Gravure Printed Flexible Electrochemical Sensor for the Detection of Heavy Metal Compounds
    Proceedings, 2018
    Co-Authors: Dinesh Maddipatla, Binu B. Narakathu, Bradley J. Bazuin, Vikram S. Turkani, Massood Z. Atashbar
    Abstract:

    An electrochemical sensor was fabricated on a flexible polyethylene terephthalate (PET) substrate for the detection of cadmium sulfide (CdS), a Heavy Metal compound. The sensor consists of a working and reference electrode that were gravure printed using silver (Ag) ink on the PET substrate. The performance of the sensor was investigated by measuring electrical impedance spectroscopy (EIS) for varying concentrations of the CdS. From the EIS based response, an impedance change of 11 ± 1%, 23 ± 1%, 34 ± 2% and 50 ± 3% was observed for the 1 pM, 1 nM, 1 µM and 1 mM concentrations of CdS, respectively when compared to de-ionized (DI) water, thus demonstrating the potential of employing gravure printed electrochemical sensors for Heavy Metal detection applications.

  • SH-SAW sensor based microfluidic system for the detection of Heavy Metal Compounds in liquid environments
    Sensors and Actuators B: Chemical, 2015
    Co-Authors: Zeinab Ramshani, Binu B. Narakathu, A. S. G. Reddy, Jared T. Wabeke, Sherine O. Obare, Massood Z. Atashbar
    Abstract:

    Abstract In this work, a guided shear horizontal mode surface acoustic wave (SH-SAW) sensor, fabricated by patterning gold (Au) interdigitated electrodes (IDE) on a 64° YX-LiNbO3 based piezoelectric substrate, was used for the detection of Heavy Metal Compounds. A flow cell, with a reservoir volume of 3 μL, which employs inlet and outlet valves for the microfluidic chamber and polydimethylsiloxane (PDMS) based microfluidic channels, was also designed and fabricated using an acrylic material. The frequency based response of the SAW sensor toward varying concentrations of Heavy Metal Compounds such as lead nitrate (PbNO3) and cadmium nitrate (CdNO3) were investigated. As the surface acoustic wave propagates on the substrate, between input and output IDEs, a shift in the resonant frequency of the SAW device was observed due to the change in velocity of the wave caused by the varying concentrations of the test analytes. The results obtained demonstrated the capability of the system to detect picomolar level concentrations. The response of the SAW sensor is analyzed and presented in this paper.

  • Opto-electrochemical based dual detection of Heavy Metal Compounds using a novel flow cell
    2013 IEEE SENSORS, 2013
    Co-Authors: Binu B. Narakathu, A. S. G. Reddy, Ali Eshkeiti, Bradley J. Bazuin, Massood Z. Atashbar
    Abstract:

    An efficient sensing system that detects Heavy Metal Compounds, by employing opto-electrochemical based dual detection technique, has been successfully developed. A novel microfluidic flow cell consisting of an inlet and outlet port with a reservoir volume of 25 μl was designed and fabricated using acrylic material. An electrochemical sensor with gold (Au) interdigitated electrodes (IDE) on a glass substrate was used for the electrical impedance spectroscopy (EIS) of various Heavy Metal Compounds. EIS performed on cadmium sulfide (CdS) and mercury sulfide (HgS) yielded picomolar (pM) concentration detection levels. Selective detection of Heavy Metal Compounds was made possible based on optical signals produced in the Raman emission spectra. The response of this dual detection sensing system is analyzed and presented in this paper.

  • Detection of Heavy Metal Compounds using a novel inkjet printed surface enhanced Raman spectroscopy (SERS) substrate
    Sensors and Actuators B-chemical, 2012
    Co-Authors: Ali Eshkeiti, Binu B. Narakathu, A. S. G. Reddy, Massood Z. Atashbar, A. Moorthi, E. Rebrosova, Marian Rebros, Margaret K. Joyce
    Abstract:

    Abstract A novel surface enhanced Raman spectroscopy (SERS) substrate was successfully fabricated on a silicon wafer using inkjet printing. Silver (Ag) nanoparticle (NP) based ink, with average particle size of 150 nm, was inkjet printed on the surface of the silicon wafer. A thickness of 400 nm was measured for the printed Ag NP film using vertical scanning interferometry. The Ag NP printed SERS substrate was tested toward Heavy Metal Compounds like cadmium sulfide (CdS), zinc oxide (ZnO) and mercury sulfide (HgS). An amplification of the SERS intensity by an order of 3–5 times was observed for all test samples, due to the presence of hotspots between the Metal nanoparticle aggregates. The responses demonstrated the feasibility of the novel SERS substrate to be used in applications for detection of Heavy Metal Compounds.

Binu B. Narakathu - One of the best experts on this subject based on the ideXlab platform.

  • A Gravure Printed Flexible Electrochemical Sensor for the Detection of Heavy Metal Compounds
    Proceedings, 2018
    Co-Authors: Dinesh Maddipatla, Binu B. Narakathu, Bradley J. Bazuin, Vikram S. Turkani, Massood Z. Atashbar
    Abstract:

    An electrochemical sensor was fabricated on a flexible polyethylene terephthalate (PET) substrate for the detection of cadmium sulfide (CdS), a Heavy Metal compound. The sensor consists of a working and reference electrode that were gravure printed using silver (Ag) ink on the PET substrate. The performance of the sensor was investigated by measuring electrical impedance spectroscopy (EIS) for varying concentrations of the CdS. From the EIS based response, an impedance change of 11 ± 1%, 23 ± 1%, 34 ± 2% and 50 ± 3% was observed for the 1 pM, 1 nM, 1 µM and 1 mM concentrations of CdS, respectively when compared to de-ionized (DI) water, thus demonstrating the potential of employing gravure printed electrochemical sensors for Heavy Metal detection applications.

  • SH-SAW sensor based microfluidic system for the detection of Heavy Metal Compounds in liquid environments
    Sensors and Actuators B: Chemical, 2015
    Co-Authors: Zeinab Ramshani, Binu B. Narakathu, A. S. G. Reddy, Jared T. Wabeke, Sherine O. Obare, Massood Z. Atashbar
    Abstract:

    Abstract In this work, a guided shear horizontal mode surface acoustic wave (SH-SAW) sensor, fabricated by patterning gold (Au) interdigitated electrodes (IDE) on a 64° YX-LiNbO3 based piezoelectric substrate, was used for the detection of Heavy Metal Compounds. A flow cell, with a reservoir volume of 3 μL, which employs inlet and outlet valves for the microfluidic chamber and polydimethylsiloxane (PDMS) based microfluidic channels, was also designed and fabricated using an acrylic material. The frequency based response of the SAW sensor toward varying concentrations of Heavy Metal Compounds such as lead nitrate (PbNO3) and cadmium nitrate (CdNO3) were investigated. As the surface acoustic wave propagates on the substrate, between input and output IDEs, a shift in the resonant frequency of the SAW device was observed due to the change in velocity of the wave caused by the varying concentrations of the test analytes. The results obtained demonstrated the capability of the system to detect picomolar level concentrations. The response of the SAW sensor is analyzed and presented in this paper.

  • Opto-electrochemical based dual detection of Heavy Metal Compounds using a novel flow cell
    2013 IEEE SENSORS, 2013
    Co-Authors: Binu B. Narakathu, A. S. G. Reddy, Ali Eshkeiti, Bradley J. Bazuin, Massood Z. Atashbar
    Abstract:

    An efficient sensing system that detects Heavy Metal Compounds, by employing opto-electrochemical based dual detection technique, has been successfully developed. A novel microfluidic flow cell consisting of an inlet and outlet port with a reservoir volume of 25 μl was designed and fabricated using acrylic material. An electrochemical sensor with gold (Au) interdigitated electrodes (IDE) on a glass substrate was used for the electrical impedance spectroscopy (EIS) of various Heavy Metal Compounds. EIS performed on cadmium sulfide (CdS) and mercury sulfide (HgS) yielded picomolar (pM) concentration detection levels. Selective detection of Heavy Metal Compounds was made possible based on optical signals produced in the Raman emission spectra. The response of this dual detection sensing system is analyzed and presented in this paper.

  • Detection of Heavy Metal Compounds using a novel inkjet printed surface enhanced Raman spectroscopy (SERS) substrate
    Sensors and Actuators B-chemical, 2012
    Co-Authors: Ali Eshkeiti, Binu B. Narakathu, A. S. G. Reddy, Massood Z. Atashbar, A. Moorthi, E. Rebrosova, Marian Rebros, Margaret K. Joyce
    Abstract:

    Abstract A novel surface enhanced Raman spectroscopy (SERS) substrate was successfully fabricated on a silicon wafer using inkjet printing. Silver (Ag) nanoparticle (NP) based ink, with average particle size of 150 nm, was inkjet printed on the surface of the silicon wafer. A thickness of 400 nm was measured for the printed Ag NP film using vertical scanning interferometry. The Ag NP printed SERS substrate was tested toward Heavy Metal Compounds like cadmium sulfide (CdS), zinc oxide (ZnO) and mercury sulfide (HgS). An amplification of the SERS intensity by an order of 3–5 times was observed for all test samples, due to the presence of hotspots between the Metal nanoparticle aggregates. The responses demonstrated the feasibility of the novel SERS substrate to be used in applications for detection of Heavy Metal Compounds.

Jochen Autschbach - One of the best experts on this subject based on the ideXlab platform.

  • relativistic zeroth order regular approximation combined with nonhybrid and hybrid density functional theory performance for nmr indirect nuclear spin spin coupling in Heavy Metal Compounds
    Journal of Chemical Theory and Computation, 2010
    Co-Authors: Salvador Moncho, Jochen Autschbach
    Abstract:

    A benchmark study for relativistic density functional calculations of NMR spin-spin coupling constants has been performed. The test set contained 47 complexes with Heavy Metal atoms (W, Pt, Hg, Tl, Pb) with a total of 88 coupling constants involving one or two Heavy Metal atoms. One-, two-, three-, and four-bond spin-spin couplings have been computed at different levels of theory (nonhybrid vs hybrid DFT, scalar vs two-component relativistic). The computational model was based on geometries fully optimized at the BP/TZP scalar relativistic zeroth-order regular approximation (ZORA) and the conductor-like screening model (COSMO) to include solvent effects. The NMR computations also employed the continuum solvent model. Computations in the gas phase were performed in order to assess the importance of the solvation model. The relative median deviations between various computational models and experiment were found to range between 13% and 21%, with the highest-level computational model (hybrid density functional computations including scalar plus spin-orbit relativistic effects, the COSMO solvent model, and a Gaussian finite-nucleus model) performing best.

  • nuclear spin spin coupling constants from regular approximate relativistic density functional calculations i formalism and scalar relativistic results for Heavy Metal Compounds
    Journal of Chemical Physics, 2000
    Co-Authors: Jochen Autschbach, Tom Ziegler
    Abstract:

    We present a relativistic formulation of the spin–spin coupling hyperfine terms based on the two component zeroth-order regular approximate Hamiltonian. The scalar relativistic parts of the resulting operators were used for an implementation into the Amsterdam density functional program. Application of the code for the calculation of one-bond Metal-ligand couplings of systems containing 183W, 195Pt, 199Hg, and 207Pb shows that scalar relativistic calculations are able to reproduce major parts of the relativistic effects on the coupling constants, which can be even larger in magnitude than the respective total nonrelativistic values. The spatial origin of the regular approximate relativistic analogue of the Fermi-contact contribution, which is usually responsible for the strong relativistic increase of the couplings, is analyzed. Its relativistic effects can be described by the relativistic increase of valence orbital density in the very vicinity of the Heavy nucleus.