scholarly journals A Friendly Complexing Agent for Spectrophotometric Determination of Total Iron

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3071
Author(s):  
Valeria M. Nurchi ◽  
Rosita Cappai ◽  
Nadia Spano ◽  
Gavino Sanna
Keyword(s):  
Accurate Determination ◽  
Iron Concentration ◽  
Total Iron ◽  
Analytical Determination ◽  
Complexing Agent ◽  
Industrial Chemistry ◽  
Spectrophotometric Methods ◽  
Desferrioxamine B ◽  
Control Serum

Iron, one of the most common metals in the environment, plays a fundamental role in many biological as well as biogeochemical processes, which determine its availability in different oxidation states. Its relevance in environmental and industrial chemistry, human physiology, and many other fields has made it necessary to develop and optimize analysis techniques for accurate determination. Spectrophotometric methods are the most frequently applied in the analytical determination of iron in real samples. Taking advantage of the fact that desferrioxamine B, a trihydroxamic acid used since the 1970s in chelation therapy for iron overload treatment, forms a single stable 1:1 complex with iron in whichever oxidation state it can be found, a smart spectrophotometric method for the analytical determination of iron concentration was developed. In particular, the full compliance with the Lambert-Beer law, the range of iron concentration, the influence of pH, and the interference of other metal ions have been taken into account. The proposed method was validated in terms of LoD, LoQ, linearity, precision, and trueness, and has been applied for total iron determination in natural water certified material and in biological reference materials such as control human urine and control serum.

scholarly journals Analytical Determination of the Slot and the End-Winding Portion of the Winding-to-Rotor Capacitance for the Prediction of Shaft Voltage in Electrical Machines

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 174
Author(s):  
Jan Ole Stockbrügger ◽  
Bernd Ponick
Keyword(s):  
Accurate Determination ◽  
Dielectric Strength ◽  
Simulation Method ◽  
Capacitive Coupling ◽  
Analytical Determination ◽  
Single Digit ◽  
Common Mode ◽  
Lubrication Film ◽  
Common Mode Voltage

Common-mode voltage, caused by a 2-level inverter, is a source of discharge currents in motor bearings. Due to the capacitive coupling, between the stator winding and the rotor, an image of the common-mode voltage is produced on the shaft—which can exceed the dielectric strength of the lubrication film of motor bearings. Accurate determination of the winding-to-rotor capacitance is necessary to predict the shaft voltage. This article proposes a novel analytical determination of the slot and the end-winding portion of the winding-to-rotor capacitance. The calculation rules, which are based on the method of image charges and the charge simulation method, take into account the continuity and the boundary conditions of the field areas. Results are validated by means of finite element method simulations. Notably, deviations are in the single-digit percentage range. Furthermore, the presented methods are simple to implement.

Determination of Lead in Soil

1972 ◽  
Vol 26 (4) ◽  
pp. 456-460 ◽  
Author(s):  
J. L. Seeley ◽  
D. Dick ◽  
J. H. Arvik ◽  
R. L. Zimdahl ◽  
R. K. Skogerboe
Keyword(s):  
Atomic Absorption ◽  
Concentration Ratio ◽  
Lead Concentration ◽  
Analytical Determination ◽  
Precision Data ◽  
Spectrophotometric Methods ◽  
Accuracy And Precision

The analytical determination of lead in soil is discussed with particular reference to emission spectrographic and atomic absorption spectrophotometric methods. The problems associated with the two techniques are discussed, and accuracy and precision data are presented. Data indicating that the titanium-to-lead concentration ratio can be used to differentiate between lead-contaminated and noncontaminated soils are presented.

Several natural indicators of radial well ageing at the Belgrade Groundwater Source, part 1

2011 ◽  
Vol 63 (11) ◽  
pp. 2560-2566 ◽  
Author(s):  
M. Dimkić ◽  
M. Pušić ◽  
D. Vidovic ◽  
A. Petković ◽  
Dj. Boreli-Zdravković
Keyword(s):  
Structural Characteristics ◽  
Iron Concentration ◽  
Total Iron ◽  
Operating Efficiency ◽  
Microbiological Parameters ◽  
Groundwater Source ◽  
Selection Of ◽  
Radial Well ◽  
The Sava River

Over time, the radial collector wells of the Belgrade Groundwater Source, located in the alluvial sediments of the Sava River, exhibit a decline in discharge and a reduction in operating efficiency due to well ageing. An increase in hydraulic losses at the lateral screens, due to chemical and biochemical clogging, has been identified as the primary cause. Certain hydrogeological, hydrochemical and microbiological parameters reflect the well-ageing process and can, therefore, be considered as its indicators. An indicator-based determination of scale is an important aspect in the selection of appropriate well locations, structural characteristics, and maintenance approaches. Well ageing was studied over a period of 5 years (2005–2009). The objective was to investigate the causes of well ageing. The correlations established between the groundwater redox potential, the total iron concentration in groundwater, the grain-size distribution of the aquifer, and well discharge, are presented in the paper.

scholarly journals Analytical Determination of the Nucleation-Prone, Low-Density Fraction of Subcooled Water

Entropy ◽  
2020 ◽  
Vol 22 (9) ◽  
pp. 933
Author(s):  
Olaf Hellmuth ◽  
Rainer Feistel
Keyword(s):  
Equation Of State ◽  
Accurate Determination ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Analytical Determination ◽  
Thermodynamic Quantities ◽  
Low Density ◽  
Water Fraction ◽  
Subcooled Water

Subcooled water is the primordial matrix for ice embryo formation by homogeneous and heterogeneous nucleation. The knowledge of the specific Gibbs free energy and other thermodynamic quantities of subcooled water is one of the basic prerequisites of the theoretical analysis of ice crystallization in terms of classical nucleation theory. The most advanced equation of state of subcooled water is the IAPWS G12-15 formulation. The determination of the thermodynamic quantities of subcooled water on the basis of this equation of state requires the iterative determination of the fraction of low-density water in the two-state mixture of low-density and high-density subcooled water from a transcendental equation. For applications such as microscopic nucleation simulation models requiring highly frequent calls of the IAPWS G12-15 calculus, a new two-step predictor-corrector method for the approximative determination of the low-density water fraction has been developed. The new solution method allows a sufficiently accurate determination of the specific Gibbs energy and of all other thermodynamic quantities of subcooled water at given pressure and temperature, such as specific volume and mass density, specific entropy, isothermal compressibility, thermal expansion coefficient, specific isobaric and isochoric heat capacities, and speed of sound. The misfit of this new approximate analytical solution against the exact numerical solution was demonstrated to be smaller than or equal to the misprediction of the original IAPWS G12-15 formulation with respect to experimental values.

Enzyme-labeled immunosorbent assay for serum ferritin: method evaluation and comparison with two radioassays.

1979 ◽  
Vol 25 (8) ◽  
pp. 1466-1469 ◽  
Author(s):  
R L Fortier ◽  
W P McGrath ◽  
S L Twomey
Keyword(s):  
Immunosorbent Assay ◽  
Inverse Relationship ◽  
Iron Concentration ◽  
Total Iron ◽  
Regression Equation ◽  
Iron Binding ◽  
Method Evaluation ◽  
Degree Of Association ◽  
Total Iron Concentration

Abstract We report our evaluation of a commercially available procedure and reagents for determination of ferritin in serum by enzyme-labeled immunosorbent assay (ELISA). Results by our procedure and the "Fer Iron" (Ramco Labs) procedure shows a degree of association (r) of 0.95 and a regression equation of y = 1.03x - 33. Similarly, our procedure compared to the "Gamma Dab" (Clinical Assays) ferritin procedure shows a degree of association of 0.98 and a regression equation of y = 0.93x - 11. Between-day standard deviations were 6 and 22 micrograms/L (n = 24 and 20) for ferritin concentrations of 20 and 300 micrograms/L, respectively. Ferritin values showed no correlation with total iron concentration, but show a broad inverse relationship with iron-binding capacities. The favorable correlation with existing procedures and the speed of the analysis commend the use of ELISA for measurement of ferritin in serum.

Experimental Study on Determination of Total Iron in Water by Automatic Discrete Spectrophotometry

2013 ◽  
Vol 807-809 ◽  
pp. 223-226
Author(s):  
Bing Tao Liu ◽  
Peng Ju Ding
Keyword(s):  
Experimental Study ◽  
Iron Concentration ◽  
Absorption Spectrometry ◽  
Total Iron ◽  
Stable Operation ◽  
Recovery Efficiency ◽  
Iron Ions ◽  
Rapid Measurement ◽  
Significant Difference

A new method was introduced for rapid measurement of iron ions in drinking water by automatic discrete spectrophotometry. In the iron concentration range 0-1.5mg/L, the linear relationship was good and the correlation coefficient was 0.9998. The total iron detection of recovery efficiency was 99.94%±1.6% and detection limit was 0.006mg/L and precision of the RSD% was 0.35%. The results show that the method was direct, fast, stable operation and lower iron concentration in water can be accurately detected.There is no significant difference compared with the results of atomic absorption spectrometry methods.

A quantitative approach to inner shell losses

1978 ◽  
Vol 36 (1) ◽  
pp. 526-527 ◽  
Author(s):  
R.D. Leapman ◽  
P. Rez ◽  
D.F. Mayers
Keyword(s):  
Energy Transfer ◽  
Cross Section ◽  
Cross Sections ◽  
Accurate Determination ◽  
Background Intensity ◽  
Core Excitation ◽  
Quantitative Basis ◽  
Cross Section Differential ◽  
Bound Electrons

Microanalysis by EELS has been developing rapidly and though the general form of the spectrum is now understood there is a need to put the technique on a more quantitative basis (1,2). Certain aspects important for microanalysis include: (i) accurate determination of the partial cross sections, σx(α,ΔE) for core excitation when scattering lies inside collection angle a and energy range ΔE above the edge, (ii) behavior of the background intensity due to excitation of less strongly bound electrons, necessary for extrapolation beneath the signal of interest, (iii) departures from the simple hydrogenic K-edge seen in L and M losses, effecting σx and complicating microanalysis. Such problems might be approached empirically but here we describe how computation can elucidate the spectrum shape.The inelastic cross section differential with respect to energy transfer E and momentum transfer q for electrons of energy E0 and velocity v can be written as

Fast calibration of CBED patterns for quantitative analysis

1993 ◽  
Vol 51 ◽  
pp. 674-675
Author(s):  
M.A. Gribelyuk ◽  
M. Rühle
Keyword(s):  
Reciprocal Lattice ◽  
Accurate Determination ◽  
Incident Beam ◽  
Crystal Thickness ◽  
Structure Model ◽  
Beam Direction ◽  
Transmitted Beam ◽  
Reciprocal Vector ◽  
On Line

A new method is suggested for the accurate determination of the incident beam direction K, crystal thickness t and the coordinates of the basic reciprocal lattice vectors V1 and V2 (Fig. 1) of the ZOLZ plans in pixels of the digitized 2-D CBED pattern. For a given structure model and some estimated values Vest and Kest of some point O in the CBED pattern a set of line scans AkBk is chosen so that all the scans are located within CBED disks.The points on line scans AkBk are conjugate to those on A0B0 since they are shifted by the reciprocal vector gk with respect to each other. As many conjugate scans are considered as CBED disks fall into the energy filtered region of the experimental pattern. Electron intensities of the transmitted beam I0 and diffracted beams Igk for all points on conjugate scans are found as a function of crystal thickness t on the basis of the full dynamical calculation.

Computer-Assisted High-Re Solution TEM

1990 ◽  
Vol 48 (1) ◽  
pp. 162-163
Author(s):  
F.A. Ponce ◽  
H. Hikashi
Keyword(s):  
Signal To Noise Ratio ◽  
Accurate Determination ◽  
Computer Software ◽  
Video Camera ◽  
Image Contrast ◽  
Objective Lens ◽  
Computer Assisted ◽  
Optical Parameters ◽  
Astigmatism Correction

The determination of the atomic positions from HRTEM micrographs is only possible if the optical parameters are known to a certain accuracy, and reliable through-focus series are available to match the experimental images with calculated images of possible atomic models. The main limitation in interpreting images at the atomic level is the knowledge of the optical parameters such as beam alignment, astigmatism correction and defocus value. Under ordinary conditions, the uncertainty in these values is sufficiently large to prevent the accurate determination of the atomic positions. Therefore, in order to achieve the resolution power of the microscope (under 0.2nm) it is necessary to take extraordinary measures. The use of on line computers has been proposed [e.g.: 2-5] and used with certain amount of success.We have built a system that can perform operations in the range of one frame stored and analyzed per second. A schematic diagram of the system is shown in figure 1. A JEOL 4000EX microscope equipped with an external computer interface is directly linked to a SUN-3 computer. All electrical parameters in the microscope can be changed via this interface by the use of a set of commands. The image is received from a video camera. A commercial image processor improves the signal-to-noise ratio by recursively averaging with a time constant, usually set at 0.25 sec. The computer software is based on a multi-window system and is entirely mouse-driven. All operations can be performed by clicking the mouse on the appropiate windows and buttons. This capability leads to extreme friendliness, ease of operation, and high operator speeds. Image analysis can be done in various ways. Here, we have measured the image contrast and used it to optimize certain parameters. The system is designed to have instant access to: (a) x- and y- alignment coils, (b) x- and y- astigmatism correction coils, and (c) objective lens current. The algorithm is shown in figure 2. Figure 3 shows an example taken from a thin CdTe crystal. The image contrast is displayed for changing objective lens current (defocus value). The display is calibrated in angstroms. Images are stored on the disk and are accessible by clicking the data points in the graph. Some of the frame-store images are displayed in Fig. 4.

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