Voltammetric Characteristics and Determination of Riboflavin at the Different Metallic Bulk Annular Band Electrodes

2018 ◽  
Vol 165 (7) ◽  
pp. H393-H398 ◽  
Author(s):  
Krystian Węgiel ◽  
Bogusław Baś
Keyword(s):  
Voltammetric Characteristics

Use Differential Pulse Voltammetry for Determining the 2,6-Ditertbutyl-4-Methylphenol in Jet Fuels

2012 ◽  
Vol 455-456 ◽  
pp. 716-720 ◽  
Author(s):  
Yong Gang Shi ◽  
Bin Su ◽  
Hai Feng Gong ◽  
Yan Xue
Keyword(s):  
Differential Pulse Voltammetry ◽  
Standard Addition ◽  
Differential Pulse ◽  
Jet Fuel ◽  
Jet Fuels ◽  
Addition Method ◽  
Electrolytic Solution ◽  
Voltammetric Characteristics ◽  
Pulse Voltammetry

A new method for determination of antioxidants in jet fuels, which is based on the differential pulse voltammetric characteristics of the antioxidant 2,6-ditertbutyl-4-methylphenol in the solution of saturated KOH anhydrous ethyl alcohols, is established. The experimental results have shown that there is a linear relationship between the content of 2,6-ditertbutyl-4-Methyl-phenol in the jet fuel and the differential pulse voltammetry response in the electrolytic solution. It has also been shown that the antioxidant contents can be reliably and simply determined with the help of the standard addition method. The largest relative error of the determination is 6.70 %, the biggest confidence for 5 samples is 1.95 mg/L (n=5, 95% confidence level).

Simultaneous determination of L-dopa and benserazide in binary mixtures using first derivative of the ratio-voltammetric methods based on their oxidation on solid electrode

2011 ◽  
Vol 76 (12) ◽  
pp. 1717-1736 ◽  
Author(s):  
B. Tolga Demircigil ◽  
Burcu Dogan-Topal ◽  
Sibel A. Ozkan
Keyword(s):  
Simultaneous Determination ◽  
Aqueous Media ◽  
Differential Pulse ◽  
Solid Electrode ◽  
First Derivative ◽  
Voltammetric Techniques ◽  
Voltammetric Characteristics ◽  
Tablet Formulations ◽  
Voltammetric Methods

The electrochemical behavior of L-dopa and benserazide at a solid electrode has been investigated using different voltammetric techniques. The anodic voltammetric characteristics of the selected compounds have been studied in aqueous media as a function of pH by cyclic, differential pulse and square wave voltammetric techniques. First derivative of the ratio voltammetric methods for determination of these compounds in their dosage forms in the presence of each other has been described. This technique depends on the measuring of the first derivative of ratio voltammograms of each concentration as a function of the increased concentrations. DP and SW voltammetric methods depend on the measuring of first derivative of the ratio voltammetry by measurements of the selected potentials corresponding to either maximums or minimums for both drugs. The linear response was within the range of 1 × 10–5–8 × 10–5 and 1 × 10–5 – 2 × 10–4 M for L-dopa and benserazide, respectively. The validity of the proposed methods was successfully assessed for analyses of both drugs in laboratory-prepared mixtures and in commercial tablet formulations. The proposed methods have successfully applied to the simultaneous determination of these compounds in the presence of each other.

scholarly journals Voltammetric characteristics of miconazole and its cathodic stripping voltammetric determination

2002 ◽  
Vol 74 (3) ◽  
pp. 425-432 ◽  
Author(s):  
FRANCISCO C. PEREIRA ◽  
NELSON R. STRADIOTTO ◽  
MARIA VALNICE B. ZANONI
Keyword(s):  
Mercury Electrode ◽  
Stripping Voltammetry ◽  
Large Contribution ◽  
Compound Formation ◽  
Cathodic Stripping Voltammetry ◽  
Voltammetric Characteristics ◽  
Relative Standard ◽  
Limit Detection ◽  
Cathodic Stripping

Miconazole is reduced at mercury electrode above pH 6 involving organometallic compound formation, responsible for an anomalous polarographic behavior. The electrodic process presents a large contribution of the adsorption effects. The drug can be determined by cathodic stripping voltammetry from 8.0 x 10-8 to 1, 5 x 10-6 molL-1 in Britton-Robinson buffer pH 8.0, when pre-accumulated for 30s at an accumulation potential of 0V. A relative standard deviation of 3.8% was obtained for ten measurements of 1.0 x 10-7 molL-1 miconazole in B-R buffer pH 8.0 and a limit detection of 1, 7 x 10-8 molL-1 was determined using 60s of deposition time and scan rate of 100 mVs-1. The proposed method is simple, precise and it was applied successfully for the determination of the miconazole in pure form and in commercial formulations, showing mean recoveries of 99.7-98.4%.

TiC Working Electrode. Voltammetric Characteristics and Application for Determination of Lead Traces by Stripping Voltammetry

2008 ◽  
Vol 20 (15) ◽  
pp. 1655-1664 ◽  
Author(s):  
B. Baś ◽  
R. Piech ◽  
E. Niewiara ◽  
M. Ziemnicka ◽  
L. Stobierski ◽  
...  
Keyword(s):  
Stripping Voltammetry ◽  
Working Electrode ◽  
Voltammetric Characteristics

Galactic orbits of stars

1966 ◽  
Vol 25 ◽  
pp. 93-97
Author(s):  
Richard Woolley
Keyword(s):  
Globular Cluster ◽  
Potential Field ◽  
High Velocity ◽  
Velocity Vector ◽  
Variable Stars ◽  
The Sun ◽  
Proper Motions ◽  
Rr Lyrae ◽  
The Galaxy

It is now possible to determine proper motions of high-velocity objects in such a way as to obtain with some accuracy the velocity vector relevant to the Sun. If a potential field of the Galaxy is assumed, one can compute an actual orbit. A determination of the velocity of the globular clusterωCentauri has recently been completed at Greenwich, and it is found that the orbit is strongly retrograde in the Galaxy. Similar calculations may be made, though with less certainty, in the case of RR Lyrae variable stars.

Distance to SN 1987A and the LMC

1999 ◽  
Vol 190 ◽  
pp. 549-554
Author(s):  
Nino Panagia
Keyword(s):  
Angular Size ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Light Curves ◽  
Distance Modulus ◽  
Absolute Size ◽  
Sn 1987A

Using the new reductions of the IUE light curves by Sonneborn et al. (1997) and an extensive set of HST images of SN 1987A we have repeated and improved Panagia et al. (1991) analysis to obtain a better determination of the distance to the supernova. In this way we have derived an absolute size of the ringRabs= (6.23 ± 0.08) x 1017cm and an angular sizeR″ = 808 ± 17 mas, which give a distance to the supernovad(SN1987A) = 51.4 ± 1.2 kpc and a distance modulusm–M(SN1987A) = 18.55 ± 0.05. Allowing for a displacement of SN 1987A position relative to the LMC center, the distance to the barycenter of the Large Magellanic Cloud is also estimated to bed(LMC) = 52.0±1.3 kpc, which corresponds to a distance modulus ofm–M(LMC) = 18.58±0.05.

International determination of the total motion of the pole

1961 ◽  
Vol 13 ◽  
pp. 29-41
Author(s):  
Wm. Markowitz
Keyword(s):  
Secular Motion ◽  
The Future

A symposium on the future of the International Latitude Service (I. L. S.) is to be held in Helsinki in July 1960. My report for the symposium consists of two parts. Part I, denoded (Mk I) was published [1] earlier in 1960 under the title “Latitude and Longitude, and the Secular Motion of the Pole”. Part II is the present paper, denoded (Mk II).

Time and Latitude in South Africa

1972 ◽  
Vol 1 ◽  
pp. 27-38
Author(s):  
J. Hers
Keyword(s):  
South Africa ◽  
Cape Town ◽  
Astronomical Observations ◽  
Royal Observatory ◽  
The Republic ◽  
Astronomical Determination ◽  
Limited Accuracy ◽  
Better Than

In South Africa the modern outlook towards time may be said to have started in 1948. Both the two major observatories, The Royal Observatory in Cape Town and the Union Observatory (now known as the Republic Observatory) in Johannesburg had, of course, been involved in the astronomical determination of time almost from their inception, and the Johannesburg Observatory has been responsible for the official time of South Africa since 1908. However the pendulum clocks then in use could not be relied on to provide an accuracy better than about 1/10 second, which was of the same order as that of the astronomical observations. It is doubtful if much use was made of even this limited accuracy outside the two observatories, and although there may – occasionally have been a demand for more accurate time, it was certainly not voiced.

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