Experimental design of ligandless sonication-assisted liquid- phases microextraction based on hydrophobic deep eutectic solvents for accurate determination of Pb(II) and Cd(II) from waters and food samples at trace levels

2022 ◽  
Vol 371 ◽  
pp. 131138
Author(s):  
Adil Elik ◽  
Ahmet Demirbaş ◽  
Nail Altunay
Keyword(s):  
Experimental Design ◽  
Accurate Determination ◽  
Deep Eutectic Solvents ◽  
Food Samples ◽  
Liquid Phases

Accurate determination of arsenic and selenium in plant food samples by using ICP-MS/MS

2016 ◽  
Vol 8 (32) ◽  
pp. 6150-6157 ◽  
Author(s):  
Xianqiao Hu ◽  
Zhaoyun Cao ◽  
Weihua Sun ◽  
Huan Yang ◽  
Ping Xu ◽  
...  
Keyword(s):  
Accurate Determination ◽  
Food Samples ◽  
Mass Shift ◽  
Plant Food ◽  
Doubly Charged Ions ◽  
Icp Ms ◽  
Doubly Charged ◽  
Charged Ions

In this paper, the influence of polyatomic and doubly charged ions on determination of As and Se was evaluated in four different modes. It was found that O2 mass-shift mode was an effective method to remove all interferences.

scholarly journals Thermodynamic Stability of Fenclorim and Clopyralid

2021 ◽  
Author(s):  
Ana R.R.P. Almeida ◽  
Bruno D.A. Pinheiro ◽  
Ana I.M.C. Lobo Ferreira ◽  
Manuel J.S. Monte
Keyword(s):  
Thermodynamic Stability ◽  
Accurate Determination ◽  
Supercooled Liquid ◽  
Drop Calorimetry ◽  
Vapor Pressures ◽  
Scanning Calorimetry ◽  
Gibbs Energies ◽  
Liquid Phases ◽  
Different Temperatures

The present work reports an experimental thermodynamic study of two nitrogen heterocyclic organic compounds, fenclorim and clopyralid, that have been used as herbicides. The sublimation vapor pressures of fenclorim (4,6-dichloro-2-phenylpyrimidine) and of clopyralid (3,6-dichloro-2-pyridinecarboxylic acid) were measured, at different temperatures, using a Knudsen mass-loss effusion technique. The vapor pressures of both crystalline and liquid (including supercooled liquid) phases of fenclorim were also determined using a static method based on capacitance diaphragm manometers. The experimental results enabled accurate determination of the standard molar enthalpies, entropies and Gibbs energies of sublimation for both compounds and of vaporization for fenclorim, allowing a phase diagram representation of the (p,T) results, in the neighborhood of the triple point of this compound. The temperatures and molar enthalpies of fusion of the two compounds studied were determined using differential scanning calorimetry. The standard isobaric molar heat capacities of the two crystalline compounds were determined at 298.15 K, using drop calorimetry. The gas phase thermodynamic properties of the two compounds were estimated through ab initio calculations, at the G3(MP2)//B3LYP level, and their thermodynamic stability was evaluated in the gaseous and crystalline phases, considering the calculated values of the standard Gibbs energies of formation, at 298.15 K.

Statistics and parallaxes

1978 ◽  
Vol 48 ◽  
pp. 7-29
Author(s):  
T. E. Lutz
Keyword(s):  
Experimental Design ◽  
Statistical Methods ◽  
Review Paper ◽  
Systematic Errors ◽  
Past Experience ◽  
Random Errors ◽  
Trigonometric Parallaxes ◽  
Systematic And Random Errors

This review paper deals with the use of statistical methods to evaluate systematic and random errors associated with trigonometric parallaxes. First, systematic errors which arise when using trigonometric parallaxes to calibrate luminosity systems are discussed. Next, determination of the external errors of parallax measurement are reviewed. Observatory corrections are discussed. Schilt’s point, that as the causes of these systematic differences between observatories are not known the computed corrections can not be applied appropriately, is emphasized. However, modern parallax work is sufficiently accurate that it is necessary to determine observatory corrections if full use is to be made of the potential precision of the data. To this end, it is suggested that a prior experimental design is required. Past experience has shown that accidental overlap of observing programs will not suffice to determine observatory corrections which are meaningful.

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