Polarographic Studies on the Nature of Cadmium in Scallop, Oyster, and Lobster

1978 ◽  
Vol 35 (4) ◽  
pp. 409-413 ◽  
Author(s):  
C. L. Chou ◽  
J. F. Uthe ◽  
E. G. Zook
Keyword(s):  
Saturated Calomel Electrode ◽  
Differential Pulse ◽  
Homarus Americanus ◽  
Atomic Absorption Spectrophotometry ◽  
Differential Pulse Polarography ◽  
American Lobster ◽  
Peak Potential ◽  
Key Words Cadmium ◽  
Muscle Tissues ◽  
Pulse Polarography

Free and bound forms of cadmium were determined in raw shellfish by use of differential pulse polarography and atomic absorption spectrophotometry. Free cadmium is defined by its polarographic peak potential of −0.62 ± 0.02 V (saturated calomel electrode) in solvent washed ammonium sulfate extracts. Bound cadmium was determined by subtracting the free cadmium from the total cadmium present in the meat. Both scallop (various species) and American lobster (Homarus americanus) muscle tissues contain no free cadmium. Oyster (various species), on the other hand, had a considerable percentage (~50%) of its total cadmium present as free cadmium, a phenomena as yet unexplained. The detection limit for free cadmium is approximately 0.05 μg/g raw tissue. Key words: cadmium, polarography; free cadmium, oyster, lobster, scallop

Determination of Copper, Nickel, and Chromium in Foods

1983 ◽  
Vol 66 (3) ◽  
pp. 620-624
Author(s):  
Walter Holak
Keyword(s):  
Anodic Stripping Voltammetry ◽  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Atomic Absorption Spectrophotometry ◽  
Differential Pulse Polarography ◽  
National Bureau ◽  
Pulse Polarography ◽  
Digestion Technique ◽  
Determination Of Copper

Abstract A collaboratively studied method for Pb, Cd, As, Se, and Zn that uses a closed system digestion technique has now been extended to include 3 additional elements, Cu, Ni, and Cr. Cu is determined by either atomic absorption spectrophotometry or anodic stripping voltammetry, depending on the concentration. Ni and Cr are determined by differential pulse polarography. Analysis of National Bureau of Standards reference materials by this procedure gives values in close agreement with the accepted values. Recoveries from applesauce and chicken spiked at 0.6-4 μg/g are in the 92-101% range. The sensitivity of the multielement procedure is 0.34,0.14, and 0.24 μg/g for Cu, Ni, Cr, respectively, at the 90% confidence level.

scholarly journals Preconcentration of Bismuth(III) and Copper(II) by Solid-Phase Extraction and Subsequent Determination by Differential Pulse Polarography

2001 ◽  
Vol 84 (1) ◽  
pp. 47-52 ◽  
Author(s):  
Anju Bhalotra ◽  
Bal Krishan Prui
Keyword(s):  
Solid Phase ◽  
Supporting Electrolyte ◽  
Saturated Calomel Electrode ◽  
Correlation Coefficients ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Pulse Polarography ◽  
Relative Standard ◽  
Microcrystalline Naphthalene

Abstract A differential pulse polarographic method is proposed for the trace determination of bismuth and copper from large volumes of aqueous samples after adsorption of their 1-(2-thiazolylazo)-2-naphthol complexes onto microcrystalline naphthalene in the pH ranges of 7.2–9.0 and 4.0–7.8, respectively. Bismuth and copper are desorbed from microcrystalline naphthalene with 9 mL 1M HCl. Well-defined peaks are obtained at Ep = −0.09 and −0.20 V versus a saturated calomel electrode, in an HCl–isoquinoline medium as the supporting electrolyte, for bismuth and copper, respectively. Bismuth is reduced reversibly with a 3-electron change, whereas copper is reduced irreversibly under these conditions. The detection limits are 55 ng/mL for bismuth and 91 ng/mL for copper. Linearity is maintained in the concentration ranges of 0.18–13.5 and 0.30-17.3 μg/mL for bismuth and copper, respectively, with corresponding correlation coefficients of 0.9996 and 0.9885. The relative standard deviations are 1.0% for bismuth at 2.0 μg/mL and 1.4% for copper at 5.0 μg/mL. Various parameters were optimized to develop conditions for the determination of these metal ions in various samples.

Theoretical Analysis of Pulse and Differential Pulse Polarography of Reversible Redox Reaction Complicated by Reactant Adsorption

2001 ◽  
Vol 66 (3) ◽  
pp. 423-433 ◽  
Author(s):  
Milivoj Lovrić ◽  
Marina Zelić ◽  
Šebojka Komorsky-Lovrić
Keyword(s):  
Theoretical Analysis ◽  
Redox Reactions ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Peak Width ◽  
Bulk Concentration ◽  
Peak Potential ◽  
Pulse Polarography ◽  
Reversible Redox ◽  
Spherical Diffusion

Pulse and differential pulse polarograms of redox reactions complicated by reactant adsorption with and without lateral attractions in the monolayer are analysed theoretically by using a stationary spherical diffusion model. The continuous shift of the post-peak potential to lower values and the decrease in its half-peak width with increasing bulk concentration of reactant indicate attractions between adsorbed ions or molecules.

Determination of Sulfites in Foods by Simultaneous Nitrogen Purging and Differential Pulse Polarography

1989 ◽  
Vol 72 (3) ◽  
pp. 476-480
Author(s):  
Walter Holak ◽  
John Specchio
Keyword(s):  
Room Temperature ◽  
Mercury Electrode ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Peak Potential ◽  
Naturally Occurring ◽  
Pulse Polarography ◽  
Dropping Mercury Electrode ◽  
Improved Technique

Abstract An improved technique has been developed for determination of sulfites in food by differential pulse polarography. A Teflon™ sleeve is fitted to the dropping mercury electrode capillary so that SO2 is purged from the sample and simultaneously detected at peak potential. Bound sulfite in the sample is released at room temperature by addition of base in the absence of oxygen. For some foods, the prepared sample was passed through a Sep-Pak C-18 cartridge to remove naturally occurring sulfur compounds so that only added sulfite is measured. The level of detection was approximately 1 μg S02/g. Results agreed with those obtained by the optimized Monier- Williams method for a variety of foods.

scholarly journals Polarographic Analysis of Structurally Modified Paracetamol

2010 ◽  
Vol 7 (s1) ◽  
pp. S43-S48
Author(s):  
Rakesh Choure ◽  
K. S. Pitre
Keyword(s):  
Organic Compound ◽  
Complex Formation ◽  
Supporting Electrolyte ◽  
Differential Pulse ◽  
Peak Height ◽  
Differential Pulse Polarography ◽  
Peak Potential ◽  
Molecular Modification ◽  
Pulse Polarography ◽  
Modified Forms

Paracetamol is an analgesic drug. Its potency may be increased by modifying the drug by way of molecular modification. In the present study the drug has been modified by its complex formation with methanol and other organic compounds. The drug organic compound interaction has been studied using differential pulse polarography and direct current polarography. In Britton Robinson buffer as supporting electrolyte of pH 7.2±0.1, paracetamol produced a well defined peak at -1.18v and it’s modified forms at relatively higher negative value. The change in peak potential and lowering in peak height indicating drug organic compound complex formation.

Determination of platinum in biological material by differential pulse polarography: Analysis in urine, plasma and tissue following sample combustion

1983 ◽  
Vol 48 (10) ◽  
pp. 2903-2908 ◽  
Author(s):  
Viktor Vrabec ◽  
Oldřich Vrána ◽  
Vladimír Kleinwächter
Keyword(s):  
Biological Material ◽  
Biological Fluid ◽  
Mercury Electrode ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Linear Calibration ◽  
Catalytic Current ◽  
Pulse Polarography ◽  
Dropping Mercury Electrode

A method is described for determining total platinum content in urine, blood plasma and tissues of patients or experimental animals receiving cis-dichlorodiamineplatinum(II). The method is based on drying and combustion of the biological material in a muffle furnace. The product of the combustion is dissolved successively in aqua regia, hydrochloric acid and ethylenediamine. The resulting platinum-ethylenediamine complex yields a catalytic current at a dropping mercury electrode allowing to determine platinum by differential pulse polarography. Platinum levels of c. 50-1 000 ng per ml of the biological fluid or per 0.5 g of a tissue can readily be analyzed with a linear calibration.

Polarography of N,N-dimethyl-4-amino-4'-hydroxyazobenzene in water-methanol mixtures

1985 ◽  
Vol 50 (3) ◽  
pp. 712-725 ◽  
Author(s):  
Jiří Barek ◽  
Lubomír Kelnar
Keyword(s):  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Polarographic Reduction ◽  
Reduction Mechanism ◽  
Pulse Polarography ◽  
Methanol Medium

The polarographic reduction of N,N-dimethyl-4-amino-4'-hydroxyazobenzene in water-methanol medium was investigated. Evidence is presented for adsorption of the depolarizer on the electrode, and a reduction mechanism is proposed. Conditions are indicated for the determination of this compound in the concentration range 10-4-10-6 mol/l by d.c. polarography, 10-5 to 3 . 10-7 mol/l by Tast polarography, and 10-5-3 . 10-8 mol/l by differential pulse polarography.

Polarographic and voltammetric determination of 6-mercaptopurine and 6-thioguanine

1986 ◽  
Vol 51 (11) ◽  
pp. 2466-2472 ◽  
Author(s):  
Jiří Barek ◽  
Antonín Berka ◽  
Ludmila Dempírová ◽  
Jiří Zima
Keyword(s):  
Detection Limit ◽  
Differential Pulse Voltammetry ◽  
Detection Limits ◽  
Differential Pulse ◽  
Voltammetric Determination ◽  
Differential Pulse Polarography ◽  
Hanging Mercury Drop Electrode ◽  
Pulse Polarography ◽  
Pulse Voltammetry

Conditions were found for the determination of 6-mercaptopurine (I) and 6-thioguanine (II) by TAST polarography, differential pulse polarography and fast-scan differential pulse voltammetry at a hanging mercury drop electrode. The detection limits were 10-6, 8 . 10-8, and 6 . 10-8 mol l-1, respectively. A further lowering of the detection limit to 2 . 10-8 mol l-1 was attained by preliminary accumulation of the determined substances at the surface of a hanging mercury drop.

The polarographic and voltammetric determination of 2,6-dicyano-4-nitro-2'-acetylamino-4'-diethylaminoazobenzene

1990 ◽  
Vol 55 (6) ◽  
pp. 1508-1517 ◽  
Author(s):  
Jiří Barek ◽  
Dagmar Civišová ◽  
Ashutosh Ghosh ◽  
Jiří Zima
Keyword(s):  
Azo Dye ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Determination Limit ◽  
Polarographic Reduction ◽  
Hanging Mercury Drop Electrode ◽  
Optimal Conditions ◽  
Pulse Polarography ◽  
Pulse Voltammetry

The polarographic reduction of the title azo dye was studied and optimal conditions were found for its analytical utilization in the concentration range 1 . 10-6 - 1 . 10-7 mol l-1 using differential pulse polarography and 1 . 10-6 - 1 . 10-8 mol l-1 using fast scan differential pulse voltammetry or linear scan voltammetry at a hanging mercury drop electrode. When the latter technique is combined with adsorptive accumulation of the studied substance on the surface of the hanging mercury drop, the determination limit can be further decreased to 3 . 10-9 mol l-1.

Polarographic and voltammetric determination of N,N’-dinitrosopiperazine

1991 ◽  
Vol 56 (7) ◽  
pp. 1434-1445 ◽  
Author(s):  
Jiří Barek ◽  
Ivana Švagrová ◽  
Jiří Zima
Keyword(s):  
Mercury Electrode ◽  
Linear Sweep Voltammetry ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Polarographic Reduction ◽  
Concentration Region ◽  
Pulse Polarography ◽  
Chemical Efficiency ◽  
Dropping Mercury Electrode

Polarographic reduction of the genotoxic N,N’-dinitrosopiperazine was studied and its mechanism was suggested. Optimum conditions were established for the determination of this substance by tast polarography over the concentration region of 1 . 10-3 to 1 . 10-6 mol l-1 and by differential pulse polarography on the conventional dropping mercury electrode or by fast scan differential pulse voltammetry and linear sweep voltammetry on a hanging mercury drop electrode over the concentration region of 1 . 10-3 to 1 . 10-7 mol l-1. Attempts at increasing further the sensitivity via adsorptive accumulation of the analyte on the surface of the hanging mercury drop failed. The methods are applicable to the testing of the chemical efficiency of destruction of the title chemical carcinogen based on its oxidation with potassium permanganate in acid solution.

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