Polarographic behaviour of petroleum components in aqueous solutions: Application of electrocapillary measurements and convective adsorption accumulation

1986 ◽  
Vol 51 (8) ◽  
pp. 1595-1603 ◽  
Author(s):  
Ladislav Novotný ◽  
Robert Kalvoda
Keyword(s):  
Surface Activity ◽  
Mercury Electrode ◽  
Diesel Oil ◽  
Analytical Determination ◽  
Polarographic Behaviour ◽  
Petroleum Fractions ◽  
Dropping Mercury Electrode ◽  
Strong Surface ◽  
Drop Time

Electrocapillary investigations by the drop time method revealed a rather strong surface activity of aqueous petroleum solutions and some petroleum fractions in solutions of base electrolytes at the dropping mercury electrode, depending on the quality of the surfactant. The highest surface activity and sensitivity of analytical determination was found between -0.4 and -0.6 V (S.C.E.). The detection limit of the electrocapillary method was 10-20 μg/l for Diesel oil and up to 5 times higher for petroleum samples. The sensitivity of the measurements at lowest concentrations was increased by convective adsorption accumulation at the surface of the growing drop.

Reduction and tensammetric pulse-polarographic currents of polynucleotides

1987 ◽  
Vol 52 (11) ◽  
pp. 2810-2818 ◽  
Author(s):  
Emil Paleček ◽  
František Jelen ◽  
Vladimír Vetterl
Keyword(s):  
Diagnostic Criteria ◽  
Pulse Width ◽  
Mercury Electrode ◽  
Pulse Amplitude ◽  
Single Strand ◽  
Pulse Polarography ◽  
Dropping Mercury Electrode ◽  
Adenylic Acid ◽  
Drop Time

The behaviour of electrochemically reducible single-strand polynucleotides (poly(adenylic acid)) and poly(cytidylic acid)) was studied by the differential (derivative) pulse polarography (DPP) and by other methods. Measurements were performed with the help of the dropping mercury electrode under various conditions specified by the pulse width, pulse amplitude, drop time etc. For the faradaic and tensammetric DPP peaks the diagnostic criteria were proposed which make it possible to classify even very small DPP peaks of double helical polynucleotides.

Polarographic Determination of 6-β-D-Glucopyranosyloxy-7-hydroxycoumarin

1996 ◽  
Vol 61 (3) ◽  
pp. 333-341
Author(s):  
Jiří Barek ◽  
Roman Hrnčíř ◽  
Josino C. Moreira ◽  
Jiří Zima
Keyword(s):  
Natural Compound ◽  
Mercury Electrode ◽  
Direct Determination ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Whitening Agent ◽  
Polarographic Behaviour ◽  
Pulse Polarography ◽  
Dropping Mercury Electrode

The polarographic behaviour was studied for 6-β-D-glucopyranosyloxy-7-hydroxycoumarin, a natural compound serving as an optical whitening agent. The substance can be quantitated by tast polarography, differential pulse polarography using a conventional dropping mercury electrode, and differential pulse polarography using a static mercury drop electrode over the regions of 20-1 000, 2-1 000, and 0.2-1 000 μmol l-1, respectively. The methods developed for the quantitation of the compound were applied to its direct determination in a raw product.

scholarly journals Analysis of Cationic Surface Active Agents Using DME and Its Relevance to Their Adsorption

1987 ◽  
Vol 4 (1-2) ◽  
pp. 53-57
Author(s):  
J. Matysik ◽  
H. Kroszka ◽  
A. Persona
Keyword(s):  
Mercury Electrode ◽  
Analytical Determination ◽  
Surface Active Agents ◽  
Dropping Mercury Electrode ◽  
Surface Active

The paper describes an application of dropping mercury electrode (DME) for analytical determination of certain cationic surface active agents and their mixtures and presents obtained thermodynamical data of adsorption of investigated substances.

Polarography of n-butylthioglycolate in aqueous media, methanol, and acetonitrile

1984 ◽  
Vol 62 (9) ◽  
pp. 1817-1821
Author(s):  
K. C. Gupta ◽  
Kalpana K. Sharma
Keyword(s):  
Aqueous Media ◽  
Mercury Electrode ◽  
Wave Characteristics ◽  
Anodic Wave ◽  
Diffusion Controlled ◽  
Dropping Mercury Electrode ◽  
Drop Time ◽  
And Diffusion ◽  
Mechanism Of The Reaction

The polarographic behaviour of n-butylthioglycolate (RSH) at the DME in aqueous media, methanol, and acetonitrile has been investigated in the presence of 0.1 M KNO3 and 0.01% thymol. The effect of pH, concentration of RSH, and drop time on the wave characteristics and the mechanism of the reaction occurring at the surface of the mercury drop have been studied. Well-defined reversible and diffusion-controlled anodic waves were obtained in aqueous media (pH 4.2), 40% methanol (pH 3.22), and 40% acetonitrile (pH 2.96). Mathematical and analytical evidence was obtained to show that the anodic wave of RSH at a dropping mercury electrode in aqueous media, 40% methanol, and 40% acetonitrile is due to the formation of the mercury complex RSHg. The dissociation constant (pK) of the mercapto group in n-butylthioglycolate is 9.6 and the diffusion coefficient in the different media are 1.17 × 10−6 cm2 s−1 (in aqueous media) 1.23 × 10−6 cm2 s−1 (in 40% methanol), and 2.43 × 10−6 cm2 s−1 (in 40% acetonitrile). The linearity of id with RSH concentration provides a rapid and precise method for the determination of RSH, down to 0.4 mM in aqueous media, methanol, and acetonitrile.

Polarographic behaviour of petroleum components in aqueous solutions: A study using DPP and convective adsorption accumulation

1986 ◽  
Vol 51 (8) ◽  
pp. 1587-1594 ◽  
Author(s):  
Robert Kalvoda ◽  
Ladislav Novotný
Keyword(s):  
Water Pollution ◽  
Aqueous Solutions ◽  
Differential Pulse ◽  
Diesel Oil ◽  
Polarographic Method ◽  
Base Electrolyte ◽  
Mercury Drop Electrode ◽  
Polarographic Behaviour ◽  
Aqueous Base

Tensametric behaviour of solutions of petroleum and its fractions in aqueous base electrolytes was studied by differential pulse polarographic method (DPP) using a stationary mercury drop electrode with adsorptive accumulation. The results indicate that water pollution with petroleum can be determined by DPP, the sensitivity of the determination depending on the quality of the pollutant and on the composition of the base electrolyte. Well utilizable calibration curves were obtained with Diesel oil at concentrations from 30-50 μl/l to 0.5 mg/l and with Saratov petroleum from 0.1-0.2 mg/l to 3.3 mg/l. Use of adsorptive accumulation led to a marked increase of the sensitivity of the analysis.

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