Assessment of Transition Metals Toxicity in Environmental Matrices Using Potentiometric Electrodes: Inorganic Mercury(II) in the Seawater as a Case Study

2015 ◽  
Vol 27 (8) ◽  
pp. 1932-1938 ◽  
Author(s):  
Marina R. A. Matos ◽  
M. Teresa S. R. Gomes ◽  
Joao A. B. P. Oliveira ◽  
Eliana Alves ◽  
M. Angela S. D. A. Cunha ◽  
...  
Keyword(s):  
Transition Metals ◽  
Inorganic Mercury ◽  
Environmental Matrices ◽  
Potentiometric Electrodes

scholarly journals OPCW Proficiency Test: A Practical Approach Also for Interlaboratory Test on Detection and Identification of Pesticides in Environmental Matrices

2014 ◽  
Vol 2014 ◽  
pp. 1-25 ◽  
Author(s):  
Leszek Konopski ◽  
Pingfeng Liu ◽  
Wuri Wuryani ◽  
Maciej Śliwakowski
Keyword(s):  
Proficiency Test ◽  
Organophosphorus Compounds ◽  
General Strategy ◽  
Chemical Weapon ◽  
Environmental Matrices ◽  
Chemical Weapon Convention ◽  
Interlaboratory Test ◽  
Detection And Identification ◽  
Standard Procedures

An overview of general strategy, standard procedures, and critical points, which may be found during carrying out an OPCW Proficiency Test concerning detection and identification of scheduled compounds relevant to Chemical Weapon Convention, has been presented. The observations have been illustrated following the case of the Eight OPCW Designated Laboratories Proficiency Test, which was performed in the OPCW Laboratory in Rijswijk in November and December 2000. Various useful hints, comments, and practical observations concerning the case study have been included as well. The same methodology and procedures may be also applied for detection, identification, and environmental analyses of pesticides and biocides, especially organophosphorus compounds.

scholarly journals Predicting the Effect of Dopants on CO2 Adsorption on Transition Metal Carbides: Case Study on TiC (001)

2020 ◽  
Author(s):  
Marti Lopez ◽  
Francesc Vines ◽  
Michael Nolan ◽  
Frances Illas
Keyword(s):  
Transition Metal ◽  
Transition Metals ◽  
Density Functional ◽  
Transition Metal Carbide ◽  
Metal Carbides ◽  
Functional Theory ◽  
Late Transition Metals ◽  
Late Transition ◽  
Early Transition

Previous work has shown that doping the TiC(001) surface with early transition metals significantly affects CO<sub>2</sub> adsorption and activation which opens a possible way to control this interesting chemistry. In this work we explore other possibilities which include non-transition metals elements (Mg, Ca, Sr, Al, Ga, In, Si, Sn) as well as late transition metals (Pd, Pt, Rh, Ir) and lanthanides (La, Ce) often used in catalysis. Using periodic slab models with large supercells and state-of-the-art density functional theory (DFT) based calculations, we show that, in all the studied cases, CO<sub>2</sub> appears as bent and, hence, activated. However, the effect is especially pronounced for dopants with large ionic crystal radii. These can increase desorption temperature by up to 230K, almost twice the value predicted when early transition metals are used as dopants. However, a detailed analysis of the results shows that the main effect does not come from electronic structure perturbations but from the distortion that the dopant generates into the surface atomic structure. A simple descriptor is proposed that would allow predicting the effect of the dopant on the CO<sub>2</sub> adsorption energy in transition metal carbide surfaces without requiring DFT calculations.

scholarly journals Validating Analytical Protocols to Determine Selected Pesticides and PCBs Using Routine Samples

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Oscar Pindado Jiménez ◽  
Susana García Alonso ◽  
Rosa María Pérez Pastor
Keyword(s):  
Water Sample ◽  
Analytical Methods ◽  
Environmental Matrices ◽  
Analytical Methodology ◽  
Water Matrix ◽  
Constant Bias ◽  
Combined Uncertainty ◽  
Sediment Matrix ◽  
Analytical Protocols

This study aims at providing recommendations concerning the validation of analytical protocols by using routine samples. It is intended to provide a case-study on how to validate the analytical methods in different environmental matrices. In order to analyze the selected compounds (pesticides and polychlorinated biphenyls) in two different environmental matrices, the current work has performed and validated two analytical procedures by GC-MS. A description is given of the validation of the two protocols by the analysis of more than 30 samples of water and sediments collected along nine months. The present work also scopes the uncertainty associated with both analytical protocols. In detail, uncertainty of water sample was performed through a conventional approach. However, for the sediments matrices, the estimation of proportional/constant bias is also included due to its inhomogeneity. Results for the sediment matrix are reliable, showing a range 25–35% of analytical variability associated with intermediate conditions. The analytical methodology for the water matrix determines the selected compounds with acceptable recoveries and the combined uncertainty ranges between 20 and 30%. Analyzing routine samples is rarely applied to assess trueness of novel analytical methods and up to now this methodology was not focused on organochlorine compounds in environmental matrices.

scholarly journals Predicting the Effect of Dopants on CO2 Adsorption on Transition Metal Carbides: Case Study on TiC (001)

2020 ◽  
Author(s):  
Marti Lopez ◽  
Francesc Vines ◽  
Michael Nolan ◽  
Frances Illas
Keyword(s):  
Transition Metal ◽  
Transition Metals ◽  
Density Functional ◽  
Transition Metal Carbide ◽  
Metal Carbides ◽  
Functional Theory ◽  
Late Transition Metals ◽  
Late Transition ◽  
Early Transition

Previous work has shown that doping the TiC(001) surface with early transition metals significantly affects CO<sub>2</sub> adsorption and activation which opens a possible way to control this interesting chemistry. In this work we explore other possibilities which include non-transition metals elements (Mg, Ca, Sr, Al, Ga, In, Si, Sn) as well as late transition metals (Pd, Pt, Rh, Ir) and lanthanides (La, Ce) often used in catalysis. Using periodic slab models with large supercells and state-of-the-art density functional theory (DFT) based calculations, we show that, in all the studied cases, CO<sub>2</sub> appears as bent and, hence, activated. However, the effect is especially pronounced for dopants with large ionic crystal radii. These can increase desorption temperature by up to 230K, almost twice the value predicted when early transition metals are used as dopants. However, a detailed analysis of the results shows that the main effect does not come from electronic structure perturbations but from the distortion that the dopant generates into the surface atomic structure. A simple descriptor is proposed that would allow predicting the effect of the dopant on the CO<sub>2</sub> adsorption energy in transition metal carbide surfaces without requiring DFT calculations.

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