Determination of Arsenic and Selenium in Foods By Electroanalytical Techniques

1976 ◽  
Vol 59 (3) ◽  
pp. 650-654 ◽  
Author(s):  
Walter Holak
Keyword(s):  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Magnesium Nitrate ◽  
Differential Pulse Polarography ◽  
Cathodic Stripping Voltammetry ◽  
Pulse Polarography ◽  
Trivalent State ◽  
Relative Standard ◽  
Cathodic Stripping

Abstract Arsenic and selenium are determined in foods by differential pulse polarography and cathodic stripping voltammetry. The sample is digested with nitric acid and magnesium nitrate and then dissolved in dilute hydrochloric acid. An aliquot is removed, the arsenic is chemically reduced to the trivalent state, and interferences are removed by ion exchange before polarography. Selenium is determined in a second aliquot by cathodic stripping voltammetry. Recoveries for both elements in several foods were from 90 to 110%. The relative standard deviations for arsenic at 5 ppm and selenium at 0.48 ppm were 5.8 and 7.3%, respectively.

Collaborative Study of the Differential Pulse Polarographic Analysis of Cacodylate Injections

1977 ◽  
Vol 60 (5) ◽  
pp. 1015-1017
Author(s):  
Walter Holak
Keyword(s):  
Supporting Electrolyte ◽  
Collaborative Study ◽  
Standard Addition ◽  
Differential Pulse ◽  
Magnesium Nitrate ◽  
Differential Pulse Polarography ◽  
Pulse Polarography ◽  
Trivalent State ◽  
Cacodylic Acid ◽  
Relative Standard

Abstract Samples containing cacodylate are heated with magnesium nitrate to decompose the cacodylate moiety, releasing pentavalent arsenic. The arsenic is reduced to the polarographically active trivalent state by heating with hydrobromic acid and hydrazine sulfate. Differential pulse polarography is performed in a 1M HQ supporting electrolyte, using a standard addition method for quantitation. The results from 6 collaborators showed an average of 97.00% of declared potency for commercial ampoules, with a relative standard deviation of 2.99%. Two synthetic cacodylic acid solutions prepared to contain 9.01 and 30.02 mg/ml gave averages of 100.03 and 99.38% of amount added, with relative standard deviations of 1.56 and 1.42%, respectively. The method has been adopted as official first action.

Possibility of determination of some derivatives of pterin important in the diagnostics of malignant tumours by using differential pulse polarography

1986 ◽  
Vol 51 (1) ◽  
pp. 34-44
Author(s):  
Václav Kočmíd ◽  
Miroslav Podolák ◽  
Jiří Čoupek ◽  
Oskar Andrýsek
Keyword(s):  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Polarographic Reduction ◽  
Malignant Tumours ◽  
Cathodic Stripping Voltammetry ◽  
Polarographic Behaviour ◽  
Pulse Polarography ◽  
Derivatives Of

The polarographic behaviour of 6,7-dimethylpterin, xanthopterin, 6-pterinaldehyde, neopterin and 6-hydroxymethylpterin was investigated. These compounds are suitably determined by employing differential pulse polarography; some results suggest the possibility of their determination by cathodic stripping voltammetry with adsorptive accumulation. For all compounds, the effect of pH on polarographic reduction was examined. Under optimal conditions, the calibration curve of all compounds under investigation was linear in the range 2 . 10-6 - 1 . 10-7 mol/l and the detection limit was below 1 . 10-7 mol/l.

Polarographic and Voltammetric Determination of Trace Amounts of 3-Nitrofluoranthene

2006 ◽  
Vol 71 (11-12) ◽  
pp. 1571-1587 ◽  
Author(s):  
Karel Čížek ◽  
Jiří Barek ◽  
Jiří Zima
Keyword(s):  
River Water ◽  
Solid Phase ◽  
Mercury Electrode ◽  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Pulse Polarography ◽  
Dropping Mercury Electrode ◽  
Separation And Preconcentration

The polarographic behavior of 3-nitrofluoranthene was investigated by DC tast polarography (DCTP) and differential pulse polarography (DPP), both at a dropping mercury electrode, differential pulse voltammetry (DPV) and adsorptive stripping voltammetry (AdSV), both at a hanging mercury drop electrode. Optimum conditions have been found for its determination by the given methods in the concentration ranges of 1 × 10-6-1 × 10-4 mol l-1 (DCTP), 1 × 10-7-1 × 10-4 mol l-1 (DPP), 1 × 10-8-1 × 10-6 mol l-1 (DPV) and 1 × 10-9-1 × 10-7 mol l-1 (AdSV), respectively. Practical applicability of these techniques was demonstrated on the determination of 3-nitrofluoranthene in drinking and river water after its preliminary separation and preconcentration using liquid-liquid and solid phase extraction with the limits of determination 4 × 10-10 mol l-1 (drinking water) and 2 × 10-9 mol l-1 (river water).

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.

Determination of Bentazepam by differential pulse polarography and adsorptive stripping voltammetry

1990 ◽  
Vol 336 (3) ◽  
pp. 222-225 ◽  
Author(s):  
Lucas Hernandez ◽  
Pedro Hernandez ◽  
Encarnacion Lorenzo ◽  
Claudio Gonzalez ◽  
Inmaculada Gonzalez
Keyword(s):  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Adsorptive Stripping Voltammetry ◽  
Differential Pulse Polarography ◽  
Pulse Polarography
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