scholarly journals DETERMINATION OF CU(II) CONCENTRATION IN AQUEOUS MEDIUM USING INVERSION ELECTROCHEMICAL METHOD

2019 ◽  
Vol 85 (7) ◽  
pp. 24-30
Author(s):  
Vera Vorobets ◽  
Gennadii Kolbasov ◽  
Sergii Fomanyuk ◽  
Nataliia Smirnova ◽  
Oksana Linnik
Keyword(s):  
Formic Acid ◽  
Ammonium Acetate ◽  
Copper Ions ◽  
Stripping Voltammetry ◽  
Acetate Buffer ◽  
Background Solution ◽  
Ammonium Acetate Buffer ◽  
Photoelectrochemical Method ◽  
Determination Of Copper

Electrode materials based on titanium dioxide modified with zinc ions and gold nanoparticles, synthesized by sol-gel method, were used to determine the concentration of Cu (II) in liquids by stripping voltammetry method. Determination of Cu (II) was done using background solutions based on 0.4 M formic acid and ammonium acetate buffer (pH = 7.5) using the standard addition method with a potential scanning speed of 50 mV•s-1. The solution was stirred during the preliminary electrolysis at a potential of -1400 mV (vs silver-chloride reference electrode) for 120 seconds and then the potential was scanned from -1200 mV to + 200 mV. It is shown that the background solution based on ammonium acetate buffer provides a higher sensitivity and a good selectivity of peaks for the determination of copper compared to the background solution based on formic acid. Determined that value of the analytical signal of copper in the studied model solutions based on ammonium acetate and formic acid is proportional to the concentration of copper ions in the solution. To increase the selectivity of stripping voltammetry method in determining copper concentrations in solutions, an inversion spectral photoelectrochemical method was proposed, the essence of which is preliminary electroconcentration of the elements under investigation in the cathode potential region and subsequent measurement of the spectral photoelectrochemical characteristics of electroconcentration products. It has been found that in solutions of 1M ammonium acetate containing Cu2+ ions, the cathodic polarization of TiO2-based photoelectrode leads to the appearance of a cathode photocurrent and the values of photocurrent quantum yield increase with increasing content of copper ions in the solution. The spectral sensitivity of the surface layer corresponds to the absorption spectrum of Cu2O. The sensitivity of stripping voltammetry method to copper Cu (II) using the materials studied was 0.3 mg•l-1. It is shown that the inversion photoelectrochemical method is promising in the selective determination of copper concentration in liquids.

scholarly journals DETERMINATION OF Cu(II) CONCENTRATION IN AQUEOUS MEDIUM USING INVERSION ELECTROCHEMICAL METHOD

2019 ◽  
Vol 85 (9) ◽  
pp. 58-64
Author(s):  
Vera Vorobets ◽  
Gennadii Kolbasov ◽  
Sergii Fomanyuk ◽  
Nataliia Smirnova ◽  
Oksana Linnik
Keyword(s):  
Formic Acid ◽  
Ammonium Acetate ◽  
Copper Ions ◽  
Stripping Voltammetry ◽  
Acetate Buffer ◽  
Background Solution ◽  
Ammonium Acetate Buffer ◽  
Photoelectrochemical Method ◽  
Determination Of Copper

Electrode materials based on titanium dioxide modified with zinc ions and gold nanoparticles, synthesized by sol-gel method, were used to determine the concentration of Cu (II) in liquids by stripping voltammetry method. Determination of Cu (II) was done using background solutions based on 0.4 M formic acid and ammonium acetate buffer (pH = 7.5) using the standard addition method with a potential scanning speed of 50 mV•s-1. The solution was stirred during the preliminary electrolysis at a potential of -1400 mV (vs silver-chloride reference electrode) for 120 seconds and then the potential was scanned from -1200 mV to + 200 mV. It is shown that the background solution based on ammonium acetate buffer provides a higher sensitivity and a good selectivity of peaks for the determination of copper compared to the background solution based on formic acid. Determined that value of the analytical signal of copper in the studied model solutions based on ammonium acetate and formic acid is proportional to the concentration of copper ions in the solution. To increase the selectivity of stripping voltammetry method in determining copper concentrations in solutions, an inversion spectral photoelectrochemical method was proposed, the essence of which is preliminary electroconcentration of the elements under investigation in the cathode potential region and subsequent measurement of the spectral photoelectrochemical characteristics of electroconcentration products. It has been found that in solutions of 1M ammonium acetate containing Cu2+ ions, the cathodic polarization of TiO2-based photoelectrode leads to the appearance of a cathode photocurrent and the values of photocurrent quantum yield increase with increasing content of copper ions in the solution. The spectral sensitivity of the surface layer corresponds to the absorption spectrum of Cu2O. The sensitivity of stripping voltammetry method to copper Cu (II) using the materials studied was 0.3 mg•l-1. It is shown that the inversion photoelectrochemical method is promising in the selective determination of copper concentration in liquids.

LC–MS/MS Determination of Apigenin in Rat Plasma and Application to Pharmacokinetic Study

2020 ◽  
Vol 21 ◽  
Author(s):  
Shixing Zhu ◽  
Jiayuan Zhang ◽  
Zhihua Lv ◽  
Mingming Yu
Keyword(s):  
Formic Acid ◽  
Pharmacokinetic Study ◽  
Ammonium Acetate ◽  
Rat Plasma ◽  
Biological Properties ◽  
Plasma Samples ◽  
Supply Rate ◽  
Natural Plant ◽  
Ammonium Acetate Buffer

Background: Apigenin, a natural plant flavone, has been shown to possess a variety of biological properties. Objective: In this report, a highly selective and sensitive LC-MS/MS method was developed and validated for the determination of apigenin in rat plasma. Methods: Analysts were separated on the HSS T3 column (1.8 μm 2.1×100 mm) using acetonitrile and 0.1% formic acid in 2 mM ammonium acetate buffer at a supply rate of 0.200 mL/min as eluent in gradient model. Results: Plasma samples were treated by protein precipitation using acetonitrile for the recovery ranging from 86.5% to 90.1% for apigenin. The calibration curves followed linearity in the concentration range of 0.50-500 ng/mL. The inter-day and intra-day precisions at different QC levels within 13.1% and the accuracies ranged from -10.6% to 8.6%. Conclusion: The assay has been successfully applied to the pharmacokinetic study of apigenin in rats.

scholarly journals Sequential Extraction of Potentially Toxic Metals: Alteration of Method for Cu-Ni Polluted Peat Soil of Industrial Barren

Toxics ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 39
Author(s):  
Marina V. Slukovskaya ◽  
Irina P. Kremenetskaya ◽  
Svetlana V. Drogobuzhskaya ◽  
Andrey I. Novikov
Keyword(s):  
Ammonium Acetate ◽  
Peat Soil ◽  
Soil Treatment ◽  
Water Soluble ◽  
Acetate Buffer ◽  
Peat Soils ◽  
Ammonium Acetate Buffer ◽  
Fraction Composition ◽  
Metal Fraction

An evaluation of fraction composition and transformation of metal compounds emitted by metal ore processing enterprises and accumulated in soils is crucial for assessing the environmental risks of pollution and ecosystem benefit of remediation. The aim of this study was to develop a suitable sequential fractional procedure for metal pollutants for the peat soils matrix in the impact zone of a Cu-Ni smelter. Three experiment series were performed: (a) the study of the effect of ammonium acetate buffer pH in the range of 3.7–7.8 on the soil metal extraction; (b) the study of the effect of additional volume and frequency of soil treatment with solutions on the content of water-soluble, ammonium acetate extractable, and 0.1 N HNO3 extractable fractions; and, (c) the determination of the metal fraction composition in the modified technique. Soil treatment with ammonium acetate buffer with a pH range of 4.5–5.5 was the most appropriate for the determination of mobile compounds of Cu and other metals in highly polluted peat soil. Triple soil treatment with water and ammonium acetate is necessary for the complete extraction of the water-soluble and exchangeable fractions, respectively. Additionally, we propose a procedure of full extraction of the exchangeable metal fraction from peat soils while using single treatment with 0.1 N HNO3. This scheme allows evaluating geochemical mobility of metals and current environmental harm of polluted soils with a high content of organic matter.

scholarly journals Estimation of Heavy Metals in Multivitamin Tablets by Differential Pulse Anodic Stripping Voltammetry

2010 ◽  
Vol 7 (s1) ◽  
pp. S169-S174 ◽  
Author(s):  
Kumar Rohit Raj ◽  
Shashank Sharma ◽  
Sachin Saxena ◽  
M. M. Srivastava ◽  
Soami P. Satsangi
Keyword(s):  
Ammonium Acetate ◽  
Anodic Stripping Voltammetry ◽  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Potential Range ◽  
Ammonium Acetate Buffer ◽  
Anodic Stripping ◽  
Drug Sample ◽  
Made In

Differential pulse anodic stripping voltammetry (DPASV) was applied for the simultaneous determination of zinc and copper in multivitamin tablet (supradyn and centrum). Determination of the metals was made in ammonium acetate buffer (pH 4.5) with a scan rate of 0.01 V/s by Hanging Mercury Dropping Electrode (HMDE).The solution was stirred during electrolysis at -1.3 V for 300 s in the potential range of -1.3 to + 0.1 V. Concentrations of zinc and copper in supradyn drug sample were found to be 1.80 and 2.9 mg/tablet and for centrum drug sample were found to be 4.6 and 0.94 mg/tablet respectively.

Polarographic Determination of Zinc in Compounded Rubber

1950 ◽  
Vol 23 (4) ◽  
pp. 975-980
Author(s):  
F. C. J. Poulton ◽  
L. Tarrant
Keyword(s):  
Zinc Oxide ◽  
Ammonium Acetate ◽  
Potassium Thiocyanate ◽  
Acetate Buffer Solution ◽  
Acid Electrolyte ◽  
Buffer Solution ◽  
Ammonium Acetate Buffer ◽  
Ammonium Acetate Buffer Solution ◽  
Gravimetric Procedure

Abstract Reasons are advanced for the unsatisfactory nature of some of the older methods for the determination of very small amounts of zinc in compounded rubber, particularly in latex mixings. The polarographic technique offers a possible solution, but most of the commoner electrolytes for the electroreduction of this metal are alkaline, and give rise to similar errors as are met in the gravimetric procedure. The development of a suitable acid electrolyte was therefore undertaken, and ways of dealing with likely interferences were examined. The electroltye finally recommended is a potassium thiocyanate-ammonium acetate buffer solution; iron, when present, is reduced to the ferrous condition by potassium iodide. The method was used to determine zinc oxide in a series of mixings of known composition ranging from 0.8 to 40 per cent. In all except the highest proportions of zinc oxide, the figures obtained agree well with the theoretical.

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