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.

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.

DEVELOPMENT OF A METHOD FOR QUANTITATIVE DETERMINATION OF THE AMOUNT OF FLAVONOIDS IN TRIPLEUROSPERMUM INODORUM’S FLOWERS

2021 ◽  
pp. 157-166
Author(s):  
Blinova O.L. ◽  
Gileva A.A. ◽  
Hlebnikov A.V. ◽  
Belonogova V.D. ◽  
Turyshev A.Y.
Keyword(s):  
Quantitative Determination ◽  
Aluminum Chloride ◽  
Chloride Solution ◽  
Uv Spectra ◽  
Raw Material ◽  
Spectral Studies ◽  
Scientific Medicine ◽  
Differential Spectrophotometry ◽  
The Stability

Chamomilla recutita is used in scientific medicine. Tripleurospermum inodorum (L.) Sch. Bip. is widely spread among possible impurities of Chamomilla recutita (L.) Rauschert. This plant is perspective for establishment into scientific medicine but it can’t change Chamomilla recutita (L.) Rauschert. Purpose of research: development of a method for the quantitative determination of the amount of flavonoids in terms of rutin in Tripleurospermum inodorum’s flowers using differential spectrophotometry. Materials and methods. The samples prepared in different parts of Russia were used as objects of research. (2017 – 2020). Spectral studies were carried out in the wavelength range of 350-430 nm with a step of 1 nm using a spectrophotometer SF-2000. Results. To determine the analytical wavelength, the UV spectra of alcohol extraction of Tripleurospermum inodorum’s flowers were studied. Maximum of absorption was noticed at wavelength 370 nm. The differential spectrum of the same extraction with an aluminum chloride solution of 2% in 96% alcohol has a maximum at a length of 410±2 nm, which coincides with the maximum of the Standard Sample (SS) of rutin. The largest number of flavonoids is extracted by 70% alcohol. The maximum optical density and the highest output of the number of flavonoids from the raw material is observed at a degree of grinding of 2 mm with a single extraction for 60 minutes. In the conditions of complexation, the optimal ratio of the volume of the test solution and aluminum chloride with a solution of 2% in 96% alcohol is the ratio of 1:1. The stability of the complex with an aluminum chloride solution of 2% in 96% alcohol is observed in 40 minutes after the start of the reaction and retains it for 30 minutes. Findings. The method is developed and the parameters of the quantitative determination of the amount of flavonoids in Tripleurospermum inodorum flores are determined in terms of rutin using differential spectrophotometry.

The Determination of Free Sulfur in Vulcanizates by a Polarographic Method

1952 ◽  
Vol 25 (1) ◽  
pp. 161-166 ◽  
Author(s):  
F. C. J. Poulton ◽  
L. Tarrant
Keyword(s):  
Quantitative Determination ◽  
Acetone Extract ◽  
Polarographic Method ◽  
The Common ◽  
Free Sulfur ◽  
Working Processes

Abstract The polarographic method offers a rapid and accurate means of determining the “true” free sulfur in vulcanizates. In the case of single estimations, the test takes approximately as long as the copper-spiral method, but for multiple or replicate testing it is much quicker. Since the determination is made directly on the acetone extract, it was necessary to examine at some length the possibility of interference from other ingredients of the extract. It is shown that most of the common accelerators and antioxidants are not likely to interfere, and promising methods of determining certain of these substances were revealed. Thus MBT, MBTS, TCA, A11, ONV, ZDC, TMT, TET, Ureka, and some of the Nonox series of antioxidants give regular Polarographic waves readily distinguishable from that of sulfur, and the development of working processes for their determination should not present any great difficulties. Other accelerators and antioxidants, notably ZIX, some Nonox antioxidants and Agerite White, while showing Polarographic activity, give poor curves in the pyridine electrolyte. No doubt in other base solutions the form of curve could be improved, and their quantitative determination would then follow.

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.

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.

New colorimetric method for quantitative determination of protein in urine.

1977 ◽  
Vol 23 (5) ◽  
pp. 811-812 ◽  
Author(s):  
H Yatzidis
Keyword(s):  
Quantitative Determination ◽  
Tannic Acid ◽  
Chloride Solution ◽  
Room Temperature ◽  
Colorimetric Method ◽  
Ferric Chloride Solution ◽  
Acid Protein ◽  
Analytical Recovery ◽  
Violet Color

Abstract Total urinary protein is rapidly precipitated at room temperature by tannic acid. The tannic acid/protein precipitate, dissolved in aqueous triethanolamine/ferric chloride solution, gives a purple-violet color of high absorptivity. Absorbance at 510 nm is linearly related to concentration from 0.05 to 1.50 A for a protein content of 0.05 to 1.50 g/liter, and less than 5 mg/liter can be detected. The CV and analytical recovery ranged from 0.5 to 1.8% and 98 to 103%, respectively. Nonprotein urinary constituents do not interfere.

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.

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.

Determination of Copper in Rubber Latex

1951 ◽  
Vol 24 (2) ◽  
pp. 472-481
Author(s):  
F. C. J. Poulton ◽  
M. E. Tunnicliffe
Keyword(s):  
Aqueous Solution ◽  
Carbon Tetrachloride ◽  
Ferric Iron ◽  
Potassium Cyanide ◽  
Zinc Salt ◽  
Colorimetric Determination ◽  
Rubber Latex ◽  
Experimental Conditions ◽  
Carbon Tetrachloride Solution

Abstract Small amounts of copper in rubber latex can be determined by following a dry-ashing procedure for removal of organic matter and concluding with a colorimetric determination of the copper in the ash. Provided the ignition is not undubly prolonged, the ashing temperature can safely rise to 800° C, and recovery of the copper is complete from the ash when a mixture of nitric and hydrochloric acids is used. Results are slightly higher than those obtained by the wet oxidation process. Assay of the copper can be carried out on the solution of the ash, either in aqueous medium or in carbon tetrachloride solution, depending on the extent of interference anticipated from iron and insoluble ingredients, such as clay, and on the degree of accuracy required. Visual color matching in aqueous solution is simpler and quicker, but insoluble material may give rise to considerable personal error. In aqueous solution, the copper equivalent of ferric iron is about 1/100, i.e., the coloration is about 100 times more intense for copper than for iron. for more accurate work, measurement of the color of a carbon tetrachloride solution of the copper diethyldithiocarbamate complex by means of a suitable colorimeter is recommended. The tendency of the complex to fade is overcome by replacing the sodium diethyldithiocarbamate by the zinc salt dissolved in carbon tetrachloride. In such a solution the copper equivalent of ferric iron is about 1/1000, but actual experimental conditions can vary this figure between wide limits. A more satisfactory procedure is, therefore, to measure the total color developed in carbon tetrachloride, and then bleach out the color due to copper with potassium cyanide. The residual (interfering) colors can thus be estimated, and the difference between the readings gives a direct measure of the concentrations of copper in the test solution.

The Quantitative Determination of Zinc in Transparent Rubber Articles

1940 ◽  
Vol 13 (1) ◽  
pp. 181-184 ◽  
Author(s):  
Edmondo Casazza
Keyword(s):  
Quantitative Determination ◽  
Zinc Content ◽  
Potassium Ferrocyanide ◽  
The Novel ◽  
Inorganic Substances ◽  
Porcelain Crucible ◽  
Zinc Salts ◽  
Concentrated Sulfuric Acid ◽  
Standard Solution

Abstract The method to be described is particularly suitable for the quantitative determination of zinc, present in the form of zinc oxide or of zinc salts, in transparent rubber articles. Rubber articles of this type contain very small quantities of zinc compared with the quantities present in non-transparent rubber articles, in fact the lower limit is only 0.05 per cent, i.e., only about one-hundredth as much as the normal content. The analytic determination of the zinc content when present in such extremely low percentages as this is extremely difficult by ordinary, methods, and even with higher but nevertheless small percentages of zinc, the use of relatively large quantities of material is necessary and the analytical results are often far from precise. The ordinary method of incineration in a porcelain crucible does not lend itself to the isolation of small quantities of zinc because the latter is easily fixed by the silica of the crucible. On the other hand incineration in a platinum crucible is not suitable because of the tendency of this metal to form a carbide in contact with the carbonaceous substances in the rubber. The novel feature of the method of analysis to be described is the procedure for obtaining a solution of the inorganic substances in the rubber. This involves destruction of the rubber by concentrated sulfuric acid and subsequent oxidation of the organic residue by concentrated nitric acid. This gives a solution of the zinc in the form of sulfate. It is then isolated as zinc sulfide and is redissolved and determined volumetrically by the already known method of precipitation with a standard solution of potassium ferrocyanide. The most suitable concentration, acidity and temperature to give precise results by this procedure for low percentages of zinc in rubber were established.

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