The Perchloric Method for the Determination of Sulfur in Rubber

1934 ◽  
Vol 7 (4) ◽  
pp. 730-735
Author(s):  
Ernest Kahane
Keyword(s):  
Nitric Acid ◽  
Perchloric Acid ◽  
Organic Substance ◽  
Present Author ◽  
General Idea ◽  
Organic Substances ◽  
Gutta Percha ◽  
Higher Temperature ◽  
As If

Abstract The problem of the determination of sulfur in rubber has been dealt with extensively in the literature, and it seems as if discussions and descriptions of new technic are nowhere nearly ended yet. The determination is so essential, and its rapid and precise execution is of such importance in industrial technic, that efforts in this direction should not be regarded as wasted. In 1926 and in 1927 Le Caoutchouc et La Gutta-Percha contained two articles in which the present author discussed the conditions of the determination of sulfur in rubber and then proposed the use of a new oxidizing mixture, not mentioned previous to that time, which involved the destruction of organic substances by perchloric acid. This method consisted simply in the attack on a 1-gram sample of rubber by 10 cc. of nitric acid (d. 1.39) and 5 cc. of perchloric acid (d. 1.61). Upon heating, attack by the nitric acid takes place, and this is followed by evaporation of the excess nitric acid, then at a little higher temperature there is an attack by the perchloric acid, which oxidizes the rest of the organic substance completely. This publication was concerned much more, in the determination of sulfur by the perchloric method, with the general idea of the destruction of organic substances than it was with the precise details of carrying it out. The technic had been studied somewhat superficially, as is shown by the text of the article itself.

scholarly journals An improvement of calcium determination technique in the shell of molluscs

2009 ◽  
Vol 52 (1) ◽  
pp. 93-98 ◽  
Author(s):  
Cristiane Soído ◽  
Maurício Carvalho Vasconcellos ◽  
Antônia Gonçalves Diniz ◽  
Jairo Pinheiro
Keyword(s):  
Hydrogen Peroxide ◽  
Nitric Acid ◽  
Experimental Model ◽  
Calcium Content ◽  
Conventional Technique ◽  
Organic Substances ◽  
Complexometric Method ◽  
Wet Weight ◽  
Calcium Determination

The complexometric method is usually applied to quantitative calcium determination in different materials; however the application of this method to calcium determination in molluscs shells infers significant interferences to the results. The snail Bradybaena similaris, a terrestrial gastropod, was used as experimental model to the improvement of this method. The shells were calcinated and dissolved in nitric acid, the hydrogen peroxide was also used to clarify the medium after the acid addition. The calcination procedure and the use of nitric acid reduced the significantly the interferences, allowing a major degree of destruction of the organic substances of the shell. The improvement of the calcium determination technique usually employed showed calcium content of 874.24 ± 56.617 mg of CaCO3/g of ash in comparison to the conventional technique that allowed the determination of 607.79 ± 67.751 mg of CaCO3/g of shell, wet weight.

The Effects of Acidic Medium on the Sodium Contents Determination by FAAS

2020 ◽  
Vol 1001 ◽  
pp. 139-144
Author(s):  
Ying Li ◽  
Ben Tao Li ◽  
Guang Yu Sun ◽  
Hui Huang ◽  
Chen Gong ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Hydrochloric Acid ◽  
Atomic Absorption Spectrometry ◽  
Flame Atomic Absorption Spectrometry ◽  
Perchloric Acid ◽  
Acidic Medium ◽  
Absorption Spectrometry ◽  
Flame Atomic Absorption ◽  
Acid Effect

The influence of different acidic medium, including hydrochloric acid, nitric acid and perchloric acid on the absorbance of sodium by flame atomic absorption spectrometry was studied. The results showed that the effects of acidic medium and water on the determination of sodium were as follows: hydrochloric acid > perchloric acid > nitric acid > water. Acid effect changed with the increase of acid concentration, however, the absorbance value of sodium element decreased when the concentration of acid was higher than 1%~2%. This effect was more obvious for high content of sodium. The detection limits, repeatability and recovery of the samples under the three acidic medium were compared. The optimum acid conditions were determined and the sensitivity of the method was improved.

A comparison between the parageneses of Fennoscandian limestone contact minerals and those of the Alnö alkaline rocks, associated with carbonates

1950 ◽  
Vol 29 (211) ◽  
pp. 304-312 ◽  
Author(s):  
Harry von Eckermann
Keyword(s):  
Present Author ◽  
General Idea ◽  
Alkaline Rocks ◽  
First Case ◽  
Younger Age

Pargas in Finland and MansjSand and Tennberg in Sweden are the only three Fennoscandian contact metamorphic limestone occurrences of which systematic accounts have been published; in the first case by A. Laitakari (1) and in the two latter ones by the present author (2, 3). A more complete analytical programme would have been desirable, and unfortunately many of the analyses are incomplete, especially as regards the determination of the valency of the iron. Nevertheless, the available data, and a few I have been able to add later, may suffice to give us a general idea of the paragenetical and chemical differences between these Archaean mineral parageneses and those of much younger age which occur in connexion with the limestone masses associated with the alkaline occurrence of Alnö in Sweden.

Turbidimetry of inorganic sulfate, ester sulfate, and total sulfur in urine.

1980 ◽  
Vol 26 (8) ◽  
pp. 1178-1181 ◽  
Author(s):  
P Lundquist ◽  
J Mårtensson ◽  
B Sörbo ◽  
S Ohman
Keyword(s):  
Polyethylene Glycol ◽  
Nitric Acid ◽  
Perchloric Acid ◽  
Barium Sulfate ◽  
Wet Oxidation ◽  
Total Sulfur ◽  
Sulfate Ester ◽  
Healthy Persons ◽  
Inorganic Sulfate

Abstract We describe simple and precise methods for the determination of inorganic sulfate, ester sulfate, and total sulfur in urine. The methods are based on turbidimetry of sulfate as barium sulfate in the presence of a small amount of preformed barium sulfate and with polyethylene glycol as a stabilizing agent. Inorganic sulfate is directly determined, whereas ester sulfate is measured after removal of inorganic sulfate, followed by acid hydrolysis. Total sulfur is determined after wet oxidation of the sample with nitric acid and perchloric acid in the presence of vanadate as a catalyst. We also report excretion values for healthy persons on a self-selected diet. Men excrete significantly higher amounts of inorganic sulfate and total sulfur than women, but this sex-related difference becomes insignificant if excretion values are expressed relative to creatinine.

Spectrophotometric Determination of Microgram Quantities of Copper in Biologic Materials

1964 ◽  
Vol 10 (9) ◽  
pp. 845-852 ◽  
Author(s):  
Ramon E Stoner ◽  
Waldemar Dasler
Keyword(s):  
Nitric Acid ◽  
Spectrophotometric Determination ◽  
Alkaline Solution ◽  
Perchloric Acid ◽  
Acid Mixture

Abstract A procedure for the determination of microgram quantities of copper in biologic material is described. The sample is wet-ashed with a nitric acid-perchloric acid mixture. The copper is extracted from an alkaline solution of the ash with a solution of diphenylcarbazide in benzene. Absorbance of the red complex is read at 540 mµ. The copper in as little as 0.5 ml. of serum can be determined and the method is suitable for routine determinations. The use of microcells makes possible the analysis of 0.1 ml. of serum.

Determination of Phosphorus in Fruits and Fruit Products by a Spectrophotometry Molybdovanadate Method and by the Official Gravimetric Quinoline Molybdate Fertilizer Method

1969 ◽  
Vol 52 (4) ◽  
pp. 865-870
Author(s):  
Ben Estrin ◽  
Wallace S Brammell
Keyword(s):  
Nitric Acid ◽  
Perchloric Acid ◽  
Colorimetric Method ◽  
Volumetric Method ◽  
Dry Ashing ◽  
Ash Weight ◽  
Molybdate Method ◽  
Phosphorus Determination ◽  
Good Agreement

Abstract A newly developed spectrophotometric molybdovanadate method and the official gravimetric quinoline molybdate fertilizer method, 2.025(b), slightly modified, were used to determine phosphorus in fruits and fruit products. In the former method, the use of hazardous perchloric acid is avoided by dry-ashing the sample as in method 20.017 and by using nitric acid rather than perchloric acid in the molybdovanadate reagent. In the quinoline molybdate method, the sample is dry-ashed in the same way. In both proposed methods, the official ash solution is used for the phosphorus determination as in the official volumetric method, 20.031–20.032. Ash weight can be obtained before preparing this solution; in the official colorimetric method, however, a second aliquot must be dry-ashed for the ash weight. The two proposed methods gave results in good agreement with those obtained by the official volumetric method. These methods are simpler and faster than the two present official methods.

scholarly journals The effect of temperature on the viscosity of air

1926 ◽  
Vol 113 (763) ◽  
pp. 233-237 ◽  
Keyword(s):  
Present Author ◽  
Effect Of Temperature ◽  
Appreciable Change ◽  
Temperature Range ◽  
Higher Temperature ◽  
The Difference ◽  
Experimental Values ◽  
Coefficient Of Viscosity ◽  
Slight Alteration

In a recent paper Prof. A. 0. Rankine has put forward a number of criticisms of the results obtained from, and the experimental method employed in, the determination of the temperature coefficient of viscosity of air by the present author. In the first place, a comparison is drawn between the author’s results and those of other observers in the lower part of the temperature range, and the conclusion is drawn therefrom that there is a possibility of an error of 3 percent, in the author’s measurements throughout the whole range of temperature used. This inference is reached from the figures quoted in Table II of Rankine’s paper, in which the temperature range from 15° to 183° C. is considered. That some difference exists between the author’s results and those of other observers in the lower part of the temperature range is clear, but it must again be emphasised that the values given for low temperatures are not experimental values, but were obtained by an extension of the graph (fig. 2) for higher temperature measurements to the value of the viscosity as given by Millikanj for room temperatures. A slight alteration of the curvature of this extension would make an appreciable change in the ratios η100/η15 and η183/η15 , but this would not be sufficient to account for the curvature at B in fig. 3 of the original paper. If the values of T ⅜ /η for Breitenbach’s results at 182° C. and 302° C. are plotted on this curve, they lie above the present results and on a curve which would intersect AB at about 600° C. That part of the difference is due to this cause seems to be indicated by the fact that the difference diminishes as the temperature rises. Thus at 300° C. the following values of η300/η15 are obtained by Breitenbach, the only other worker at this temperature, and the author. The figures used are those given by Rankine.

Simple, Rapid Digestion Technique for the Determination of Mercury in Fish by Flameless Atomic Absorption

1972 ◽  
Vol 55 (4) ◽  
pp. 741-742 ◽  
Author(s):  
Walter Holak ◽  
Benjamin Krinitz ◽  
John C Williams
Keyword(s):  
Nitric Acid ◽  
Atomic Absorption ◽  
Perchloric Acid ◽  
Closed System ◽  
Acid Digestion ◽  
Flameless Atomic Absorption ◽  
Digestion Technique ◽  
Mercury In Fish

Abstract A simple and rapid digestion technique is described for the determination of mercury in fish by flameless atomic absorption. The sample is digested with nitric acid in a closed system in a commercially available vessel made of Teflon. A 30 min digestion at 150 °C is sufficient to convert the mercury to an inorganic form so that it can t h e n be reduced to the elemental state , aerated, and determined by atomic absorption. The proposed digestion compares favorably with the official AOAC sulfuricnitric- perchloric acid digestion.

Determination of Sulfur in Rubber by the Perchloric Acid Method

1929 ◽  
Vol 2 (1) ◽  
pp. 45-55 ◽  
Author(s):  
Edward Wolesensky
Keyword(s):  
Nitric Acid ◽  
Hydrochloric Acid ◽  
Sulfur Content ◽  
Perchloric Acid ◽  
Steam Bath ◽  
Accurate Method ◽  
Dilute Solution ◽  
Sodium Peroxide ◽  
Rubber Compounds

Abstract In a search for a rapid and accurate method for determining sulfur in rubber it was found that oxidation of the sample by means of sodium peroxide in the Parr bomb is unsatisfactory when the sulfur content of the rubber is low because the samples that can be used for this purpose are too small for accurate results, or, if larger samples are used, the oxidation is incomplete. The use of a mixture of nitric and perchloric acids, as described by Kahane, is also unsatisfactory; but with certain modifications the method may be made to yield very good results, and if fusions are unnecessary, it will save time and labor. The chief modifications recommended are the use of a more dilute solution of nitric acid (equal volumes of the concentrated acid and water), allowing the rubber to dissolve completely on the steam bath before heating more strongly, then heating to gentle boiling until oxidation is complete, and finally destroying the residual nitric acid by means of hydrochloric acid. The use of a larger flask (500 to 800 cc.) is also recommended, and suggestions are also made for the adaptation of this method to the analysis of those rubber compounds which contain barium, lead, etc.

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