Examination of the potential of copper during its dissolution in sodium hydroxide

1981 ◽  
Vol 46 (12) ◽  
pp. 3057-3062 ◽  
Author(s):  
Petr Sušinka ◽  
Milica Miadoková
Keyword(s):  
Quantitative Determination ◽  
Sodium Hydroxide ◽  
Oxygen Electrode ◽  
Quantitative Relation ◽  
Experimental Conditions ◽  
Kinetic Measurements ◽  
Crystallographic Planes ◽  
The Given ◽  
Spontaneous Reaction

Parallel to kinetic measurements, the potential of copper was monitored on the (100), (110), and (111) crystallographic planes during its spontaneous reaction in sodium hydroxide in oxygen atmosphere. A quantitative relation was obtained for the potential in dependence on the experimental conditions, indicating that unless a passivating layer of copper(II) oxide is formed on the surface, the metal does not act as an oxygen electrode. The potential change in the given medium was found to depend only on the amount of copper(I) oxide formed, obeying the relation E = (RT/nF) ln (mCu2O) + K; use was made of this relation for a quantitative determination of the growth of the copper(I) oxide layer.

Free-base corroles: determination of deprotonation constants in non-aqueous media

2007 ◽  
Vol 11 (04) ◽  
pp. 269-276 ◽  
Author(s):  
Jing Shen ◽  
Zhongping Ou ◽  
Jianguo Shao ◽  
Michał Gałęzowski ◽  
Daniel T. Gryko ◽  
...  
Keyword(s):  
Equilibrium Constants ◽  
Aqueous Media ◽  
Free Base ◽  
Organic Base ◽  
Experimental Conditions ◽  
Spectral Changes ◽  
Base Analysis ◽  
Uv Visible ◽  
The Given

A series of free-base corroles with different electron-donating or electron-withdrawing substituents were reacted with piperidine, 4-aminopyridine, 2-methylimidazole, 2-aminopyridine or pyridine in PhCN and the UV-visible spectral changes monitored during conversion of ( Cor ) H 3 to [( Cor ) H 2]- as a function of the concentration and strength of the added organic base. Analysis of the UV-visible spectral changes as a function of the added base concentration enabled calculation of equilibrium constants ( logK ) for deprotonation of each corrole under the given experimental conditions. Relationships are examined between the experimentally measured logK values and previously published spectroscopic and structural properties of the compounds.

2-(2'- Chloro Phenyl)- 5- (2'-Hydroxyl Phenyl)-1,3,4-Oxadiazole as a Florescent Probe for DNA Determination

2011 ◽  
Vol 301-303 ◽  
pp. 361-365
Author(s):  
Mei Ding ◽  
Ying Jie Lei ◽  
Ou Yang Jie
Keyword(s):  
Experimental Data ◽  
Fluorescence Quenching ◽  
Quantitative Determination ◽  
Fluorescent Probe ◽  
Fluorescence Intensity ◽  
Dna Analysis ◽  
Fluorescence Spectrometry ◽  
Experimental Conditions ◽  
Convenient Synthesis

In recent years, fluorescence spectrometry was widely used in quantitative determination of DNA. In this paper, a convenient synthesis of a new fluorescent 2-(2'- Chloro phenyl)- 5- (2'- hydroxyl phenyl)-1,3,4-oxadiazole (HOXD) was realized. Experimental data showed that fluorescence of HOXD could be quenched by DNA and the decreased fluorescence intensity of HOXD resulting from fluorescence quenching is proportional to DNA concentrations suggesting that HOXD could be used as a new fluorescent probe for quantitative determination of DNA. Optimal experimental conditions for DNA analysis were also studied in the paper.

The Identification Analysis for Macro Distributions Curves of Functionally Graded Materials Properties Based on Materials Components

2011 ◽  
Vol 228-229 ◽  
pp. 50-54
Author(s):  
Chao Feng Ge
Keyword(s):  
Functionally Graded Materials ◽  
Functionally Graded ◽  
Experimental Conditions ◽  
Graded Materials ◽  
Materials Properties ◽  
Dynamic Analyses ◽  
Identification Technique ◽  
Identification Analysis ◽  
The Given

There are much complex internal microstructures of functionally graded materials, and the mechanical parameters of functionally graded materials structures varied with the space coordinates. Therefore, it is generally difficult to measure point by point macro distributions curves of functionally graded materials properties based on available experimental conditions. The prerequisite for various analyses of the functionally graded materials structures is the determination of macro distributions curves of materials properties parameters. In practice, only the spatial distributions of different material components can be controlled in the course of materials production. Therefore, the functionally graded distributions curves need inversing and identifying by the materials components. In the present paper, the inversion and identification technique was put forward based on the positive static and dynamic analyses by the microelement method, which was applied to do the scale-span analyses for macro responses of functionally graded materials structures based on the given materials components distributions in production.

scholarly journals A New Technique for Quantitative Determination of Dexamethasone in Pharmaceutical and Biological Samples Using Kinetic Spectrophotometric Method

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Ali Mohammad Akhoundi-Khalafi ◽  
Masoud Reza Shishehbore
Keyword(s):  
Quantitative Determination ◽  
Spectrophotometric Method ◽  
Biological Samples ◽  
Reaction System ◽  
Calibration Graph ◽  
Experimental Conditions ◽  
Orange G ◽  
A New Technique ◽  
Kinetic Spectrophotometric

Dexamethasone is a type of steroidal medications that is prescribed in many cases. In this study, a new reaction system using kinetic spectrophotometric method for quantitative determination of dexamethasone is proposed. The method is based on the catalytic effect of dexamethasone on the oxidation of Orange G by bromate in acidic media. The change in absorbance as a criterion of the oxidation reaction progress was followed spectrophotometrically. To obtain the maximum sensitivity, the effective reaction variables were optimized. Under optimized experimental conditions, calibration graph was linear over the range 0.2–54.0 mg L−1. The calculated detection limit (3sb/m) was 0.14 mg L−1for six replicate determinations of blank signal. The interfering effect of various species was also investigated. The present method was successfully applied for the determination of dexamethasone in pharmaceutical and biological samples satisfactorily.

The Quantitative Determination of Rubber Chemicals

1957 ◽  
Vol 30 (4) ◽  
pp. 1017-1026 ◽  
Author(s):  
Otto Lorenz ◽  
Elisabeth Echte
Keyword(s):  
Quantitative Determination ◽  
Chloride Solution ◽  
Silver Salt ◽  
Stannous Chloride ◽  
Zinc Salt ◽  
Iodine Solution ◽  
Experimental Conditions ◽  
Zinc Salts ◽  
Free Sulfur

Abstract 1. Both the precipitation of mercaptobenzothiazole as a silver salt and its oxidation with an iodine solution to a disulfide may be utilized for quantitative determination. 2. Zinc benzothiazolyl mercaptide can be determined iodometrically, either directly or indirectly, after being cleaved by acids. 3. Benzothiazolyl disulfide is determined as mercaptobenzothiazole after reduction with acidic stannous chloride solution. 4. A procedure for the determination of a mixture of mercaptobenzothiazole, zinc benzothiazolyl mercaptide, and dibenzothiazolyl disulfide is described. 5. Experimental conditions are indicated, under which the quantitative determination of free sulfur is possible in the presence of mercaptobenzothiazole, its zinc salt, the disulfide, and the zinc salts of fat acids. In all cases the uncombined sulfur is determined after its conversin to thiocyanate by an argentometric conductivity titration of the thiocyanate.

scholarly journals A New Approach for the Determination of Benzocaine and Procaine in Pharmaceuticals by Single-Sweep Polarography

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Serhij Plotycya ◽  
Oksana Strontsitska ◽  
Solomiya Pysarevska ◽  
Mykola Blazheyevskiy ◽  
Liliya Dubenska
Keyword(s):  
Quantitative Determination ◽  
Oxidation Products ◽  
Polarographic Reduction ◽  
Polarographic Method ◽  
Experimental Conditions ◽  
New Approach ◽  
Reduction Current ◽  
Product Specifications ◽  
Good Agreement

A new polarographic method for the determination of benzocaine and procaine based on the polarographic reduction of their chemically obtained oxidation products with potassium peroxymonosulfate is developed. Experimental conditions affecting quantitative yield of benzocaine and procaine oxidation products such as рH, oxidation time, reagents’ concentration, and temperature are explored. It is shown that the reduction current changes in a linear fashion (R=0.999) with increasing concentration of anesthetics over a concentration range of 1·10−6 - 5·10−5 mol L−1. The calculated limits of detection (LOD) for benzocaine and procaine are found to be 5.6·10−6 and 6·10−6 mol L−1, respectively. In the present study, quantitative polarographic determination of benzocaine in Farisil tablets and “Septolete Plus” lozenges and procaine in solution for injections is performed. The results of the analysis are in good agreement with the product specifications described in the quality certificates. The possibility of quantitative determination of benzocaine and procaine in pharmaceuticals is confirmed.

Polarographic Determination of Accelerators, Antioxidants, and Other Rubber Chemicals. I.

1959 ◽  
Vol 32 (4) ◽  
pp. 1254-1268
Author(s):  
F. Mocker
Keyword(s):  
Zinc Oxide ◽  
Quantitative Determination ◽  
Raw Materials ◽  
Zinc Stearate ◽  
Zinc Salt ◽  
Polarographic Method ◽  
Experimental Conditions ◽  
Methanolic Extracts ◽  
Rubber Compounds

Abstract The present paper shows that the Polarographic method for the determination of rubber additives (rubber chemicals) delivers fully usable results. The following points are discussed : 1. The method is qualified for a rapid quantitative determination of MBT and 2-mercaptobenzimidazole in raw materials control. 2. The zinc salt of MBT can be indirectly determined after its decomposition with acid. 3. MBT and 2-mercaptobenzimidazole can be determined directly in the methanolic extracts of masterbatches. 4. As with the masterbatches, MBT can be determined directly in the extracts of rubber stocks and vulcanizates when zinc oxide is absent. Magnesium oxide or zinc stearate do not interfere. 5. Experimental conditions are given which permit quantitative determinations of MBT in the presence of zinc oxide in uncured and cured rubber compounds. 6. The experiments have shown that the method is applicable to complex recipes containing MBT as the only accelerator. Of course, the limit of error is higher, that is, around −5%. The investigations are being continued and the results will be presented at a later date.

The simultaneous determination of Fe(III) and Cu(II) in the presence of Zn(II) using 2-(5-bromo-2-pyridylazo)-5-(diethylamino)phenol

1988 ◽  
Vol 53 (12) ◽  
pp. 3040-3049 ◽  
Author(s):  
Vladimír Buršík ◽  
Vlastimil Kubáň ◽  
Lumír Sommer
Keyword(s):  
Simultaneous Determination ◽  
Copper Ions ◽  
Ternary Mixtures ◽  
Experimental Conditions ◽  
Spectrophotometric Methods ◽  
Chelate Formation ◽  
Binary And Ternary Mixtures ◽  
Triton X ◽  
The Given

Spectrophotometric methods were employed to study the chelate formation between Fe(III) ions and 2-(5-bromo-2-pyridylazo)-5-(diethylamino)phenol (BrPADAP) in dimethylformamide (φ = 20%) and Triton X-100 (φ = 0·1%). The ML2 chelate with absorption maxima at 535 and 590 nm and molar absorption coefficients of 6·5 and 8·2 m2 mmol-1 is formed quantitatively in the pH interval 3·5 - 4·0 for at least a seven-fold concentration excess of BrPADAP. Concentrations of c(Fe) = 1·6 - 8·1 μmol l-1 can be determined independently in 0·1M acetate buffer with pH 3·6. Iron and copper ions can be determined simultaneously in the presence of zinc ions in binary or ternary mixtures in the concentration ranges c(Fe) = 2 - 8 μmol l-1 and c(Cu) = c(Zn) = 3 - 16 μmol l-1. The relative deviations in the calculated concentrations, Δcr, are 1 - 4% for Fe and up to 5% for Cu in binary and ternary mixtures with equivalent concentrations up to a concentration excess of one component of five-fold in binary mixtures or of one or two components of up to three-fold in ternary mixtures. The simultaneous determination of Zn(II) is accompanied by a Δcr value of up to 30 - 50% and cannot be recommended under the given experimental conditions.

scholarly journals Quantitative Determination of Acetamiprid in Pollen Based on a Sensitive Enzyme-Linked Immunosorbent Assay

Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1265 ◽  
Author(s):  
Qingkui Fang ◽  
Quan Zu ◽  
Xiude Hua ◽  
Pei Lv ◽  
Wanwen Lin ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Detection Limit ◽  
Quantitative Determination ◽  
Immunosorbent Assay ◽  
Linear Range ◽  
Enzyme Linked Immunosorbent Assay ◽  
Experimental Conditions ◽  
Coating Antigen ◽  
Relative Standard

A sensitive biotinylated indirect competitive enzyme-linked immunosorbent assay (Bic-ELISA) was developed to detect acetamiprid pesticides in pollen, based on the heterogeneous coating antigen and biotinylated anti-acetamiprid monoclonal antibody. Under optimized experimental conditions, the detection limit for the Bic-ELISA was 0.17 ng/mL and the linear range was 0.25–25 ng/mL. The cross-reactivities could be regarded as negligible for the biotinylated antibodies with their analogues except for thiacloprid (1.66%). Analyte recoveries for extracts of spiked pollen (camellia pollen, lotus pollen, rape pollen) ranged from 81.1% to 108.0%, with intra-day relative standard deviations (RSDs) of 4.8% to 10.9%, and the average reproducibility was 85.4% to 110.9% with inter-assay and inter-assay RSDs of 6.1% to 11.7%. The results of Bic-ELISA methods for the Taobao’s website samples were largely consistent with HPLC-MS/MS. Therefore, the established Bic-ELISA methods would be conducive to the monitoring of acetamiprid in pollen.

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