THE APPLICATION OF 8-HYDROXYQUINOLINE TO THE ANALYSIS OF ALUMINIUM ALLOYS: DETERMINATION OF MAGNESIUM IN THE PRESENCE OF MANGANESE AND NICKEL

1945 ◽  
Vol 23b (5) ◽  
pp. 183-193
Author(s):  
Paul E. Gagnon ◽  
Henri Shehyn
Keyword(s):  
Sodium Chloride ◽  
Hydrochloric Acid ◽  
Aluminium Alloys ◽  
Accurate Method ◽  
Salting Out ◽  
Co Precipitation ◽  
Short Method

The application of the precipitation of magnesium with oxine in tartro–sodic medium to the analysis of aluminium alloys has been studied from the standpoint of possible interference from other constituents of the alloys and especially manganese and nickel. In the presence of manganese in amounts not exceeding 8.0 mgm. per 100 ml. of solution, magnesium can be successfully determined provided sodium chloride is not present. With amounts of sodium chloride exceeding 6 gm. and manganese over 6 mgm. per 100 ml. of solution, a salting-out of manganese oxinate definitely takes place which leads to high results for magnesium. This interference can be eliminated by preventing the formation of appreciable amounts of sodium chloride by evaporating off hydrochloric acid before adjusting the pH for the precipitation of magnesium oxinate. Nickel in amounts exceeding 2.5 mgm. per 100 ml. of solution interferes by co-precipitation of nickel oxinate, which is adsorbed on the magnesium oxinate and finally leads to high values for magnesium. For this reason, nickel must be removed by means of an ammonium sulphide separation for which a short method is described. With these modifications the precipitation of magnesium with oxine in tartro–sodic medium provides a rapid and accurate method of determining this element in aluminium alloys.

DETERMINATION OF TRACE AMOUNTS OF SILVER IN GALENA ORES

1960 ◽  
Vol 38 (9) ◽  
pp. 1488-1494 ◽  
Author(s):  
E. J. Bounsall ◽  
W. A. E. McBryde
Keyword(s):  
Aqueous Solution ◽  
Nitric Acid ◽  
Sodium Chloride ◽  
Hydrochloric Acid ◽  
Chloride Solution ◽  
Sodium Chloride Solution ◽  
Silver Content ◽  
Aqueous Sodium Chloride Solution ◽  
Aqueous Sodium

An analytical method is described for the determination of microgram amounts of silver in galena ores, based on the "reversion" of silver dithizonate. Silver is separated from relatively large amounts of lead by extraction as dithizonate into chloroform from an aqueous 1:99 nitric acid solution. Separation from mercury, which is also extracted under these conditions and would, if present, interfere in the analysis, is achieved by reverting the dithizonate solution with a 5% aqueous sodium chloride solution which is also 0.015 molar in hydrochloric acid. Following dilution of this aqueous solution and adjustment of pH, silver is again extracted into chloroform as the dithizonate, and determined absorptiometrically. Analyses of a number of galena ore samples showed a precision of within 3% for a silver content ranging from 0.03 to 0.4%.Some other methods for isolating silver from these samples, which were tried but found unsatisfactory, are discussed.

SOME FACTORS AFFECTING THE DETERMINATION OF FURFURAL

1948 ◽  
Vol 26b (3) ◽  
pp. 314-324 ◽  
Author(s):  
G. A. Adams ◽  
A. E. Castagne
Keyword(s):  
Sodium Chloride ◽  
Hydrochloric Acid ◽  
Steam Distillation ◽  
Plant Residues ◽  
Titration Method ◽  
Photocolorimetric Determination ◽  
Factors Affecting ◽  
Photocolorimetric Method ◽  
Negative Results

The previous observation by Stillings and Browning that methylfurfural and hydroxymethylfurfural do not interfere with the photocolorimetric determination of furfural with aniline has been confirmed. The color of the furfural – aniline acetate compound was stabilized satisfactorily by oxalic acid and sodium chloride; the addition of disodium phosphate brought about minimum transmittance. Recoveries of furfural distilled from 12% hydrochloric acid were 99.0 and 99.7% as measured by the photocolorimetric and excess bromine titration methods respectively. Xylose was converted to furfural in 90.6% yield by simple distillation with 12% hydrochloric acid saturated with sodium chloride. Rapid steam distillation increased the recovery to 91.6%. Dextrose, levulose, cellulose and rhamnose gave apparent furfural yields by the excess bromine titration method but negative results with the photocolorimetric method. The two methods were applied to 13 plant residues whose furfural contents ranged from more than 30% in 'Beewing' wheat bran to less than 5% for peat. The results obtained by the photocolorimetric method, regarded as being the true furfural contents, are 2 to 3% lower than those obtained by the titration method.

Determination of Carbon Dioxide in Cucumber Brines

1974 ◽  
Vol 57 (1) ◽  
pp. 130-133 ◽  
Author(s):  
Henry P Fleming ◽  
Roger L Thompson ◽  
JOHN L Etchells
Keyword(s):  
Carbon Dioxide ◽  
Hydrochloric Acid ◽  
Acid Solution ◽  
Sample Size ◽  
Sodium Hydroxide ◽  
Small Sample Size ◽  
Accurate Method ◽  
Small Sample ◽  
Small Vial

Abstract A simple, accurate method for determining carbon dioxide in fermenting cucumber brines is described. The method involves distillation of carbon dioxide from the acidified brine into standardized sodium hydroxide inside a closed jar. The sample is injected by a syringe and needle through a rubber serum stopper placed in the jar cap, into an acid solution. A small vial of sodium hydroxide placed inside the jar traps the carbon dioxide as it distills from the acidified solution. After being held in the jar 24 hr at 37°C, the vial is removed; the remaining base is titrated to the phenolphthalein end point with standardized hydrochloric acid. Advantages of the method include a limited working time, minimized loss of carbon dioxide during analysis, and a relatively small sample size.

Determination of 234U and 238U in seawater samples by alpha spectrometry after concentration of U(VI) onto hydrotalcite and co-precipitation with LaF3

2013 ◽  
Vol 101 (10) ◽  
pp. 621-624
Author(s):  
N. V. Suc ◽  
T. T. Bich
Keyword(s):  
Inductively Coupled Plasma ◽  
Alpha Spectrometry ◽  
Separation Efficiency ◽  
Chemical Separation ◽  
Accurate Method ◽  
Uranium Isotopes ◽  
Inductively Coupled ◽  
Seawater Samples ◽  
Co Precipitation

Summary This paper presents a simple and accurate method for determination of uranium isotopes (234U and 238U) in seawater samples using alpha spectrometry. Uranium is pre-concentrated from seawater samples via adsorption on hydrotalcite at pH 6.5. The absorbent is dissolved into 50 ml of 8M HNO3; then filtered through a Dowex-1 column. U(VI) in the elution solution is reduced to U(IV) using zinc metal in 4M solution of HCl and then co-precipitated with LaF3. The chemical separation efficiency is found to be 97.12±2.68%, eliminating the need of using 232U tracer in other published methods. This method is validated via comparison with results obtained using inductively coupled plasma mass spectrometry (ICP-MS) and neutron activation analysis (NAA) for three seawater samples.

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.

scholarly journals Development and validation of a method for isolating stavudine from biological fluids

2021 ◽  
Vol 24 (1) ◽  
pp. 62-68
Author(s):  
Daria A. Borodina ◽  
Yulia A. Gonchikova ◽  
Elena A. Illarionova ◽  
Anastasia E. Mitina
Keyword(s):  
Sodium Chloride ◽  
Hydrochloric Acid ◽  
Acid Solution ◽  
Blood Plasma ◽  
Ammonium Sulfate ◽  
Biological Fluids ◽  
Liquid Extraction ◽  
Uv Spectrophotometry ◽  
Liquid Liquid Extraction

Objective - study of isolating Stavudine from biological fluids (urine, blood plasma). Materials and methods. Objects of research: substance and tablets of 30 mg Stavudine. Reagents: purified water, chloroform, ethyl acetate, dichloromethane, ether, heptane, toluene, acetone, 95% ethyl alcohol, 0.1 M hydrochloric acid solution, 10% ammonium hydroxide solution, 5%solutions of sodium sulfate, 20%sodium sulfate saturated, sodium chloride, sodium chloride saturated, 20%ammonium sulfate, ammonium sulfate saturated. Universal ionomer IT-1101. Stavudine was isolated by liquid-liquid extraction. To detect and quantify Stavudine, thin - layer sorbent chromatography (TLC) and UV spectrophotometry were used. Statistical data processing was performed using the software package for Windows XP (Microsoft Excel), and using the Student's t-test. Results. When using thin-layer chromatography to identify Stavudine, it was found that the Rf value of the spots of Stavudine extracts from biological material corresponded to the Rf value range of 0.67-0.69. The Rf spot value of the standard Stavudine witness sample corresponded to (0.68±0.01). The stability study showed that the Stavudine solution is stable in a hydrochloric acid solution of 0.1 M, in which the absorption spectrum of Stavudine is characterized by absorption maxima at wavelengths of 209±1 and 267±1 nm. The wavelength of 267±1 nm was chosen as the analytical wavelength for the quantitative determination of Stavudine. In the course of the study, various factors affecting the degree of extraction of Stavudine from aqueous solutions were studied. The extractant is ethyl acetate, pH 3, the electrolyte is a saturated solution of ammonium sulfate. The extraction time is 7 minutes, twice. Conclusion. Methods of identification and quantitative determination of Stavudine in extracts from urine and blood plasma by TLC and UV spectrophotometry have been developed. Methods of isolation of Stavudine from urine and blood plasma using the liquid-liquid extraction method have been developed (93.33±2.02%; 89.77±2.02% respectively).

Extraction and Determination of RDX and HMX in Water

1999 ◽  
Vol 34 (3) ◽  
pp. 533-544 ◽  
Author(s):  
Eny M. Vieira ◽  
Francis I. Onuska
Keyword(s):  
Sodium Chloride ◽  
Solid Phase Extraction ◽  
Ammonium Sulfate ◽  
Organic Phase ◽  
Lake Water ◽  
Energetic Materials ◽  
Solid Phase ◽  
Phase Extraction ◽  
Salting Out

Abstract The analysis of energetic materials such as RDX and HMX in water at trace levels was accomplished by using micro-extraction by miscible solvents, such as acetonitrile, 2-propanol and acetone, and salting out the organic phase. This paper compares the results obtained with solid-phase extraction (SPE) to those obtained by demixing techniques for spiked Milli-Q water and an unfiltered lake water. A review of the data indicates that demixing with acetonitrile-sodium chloride and 2-propanol ammonium sulfate gives better extraction recoveries than solid-phase extraction. Salting-out extractions are performed in less time and with less solvent than by SPE techniques.

Determination of Fluoride in Antarctic Krill Euphausia superba Using Ion Chromatography

2013 ◽  
Vol 842 ◽  
pp. 210-215
Author(s):  
Xiao Sheng Shen ◽  
Hai Yan Zhang ◽  
Yan Lin Li ◽  
You Qiong Cai
Keyword(s):  
Hydrochloric Acid ◽  
Ion Chromatography ◽  
Antarctic Krill ◽  
Limit Of Detection ◽  
Euphausia Superba ◽  
Accurate Method ◽  
Acid Extraction ◽  
Key Words Fluoride ◽  
Optimum Extraction

A simple, rapid and accurate method for the determination of fluoride in Antarctic krill has been developed. The fluoride content in Antarctic krill was determined by ion chromatography. The method requires a simple sample clean-up procedure to remove the interfering Cl- from the hydrochloric acid extraction solution. The optimum extraction conditions of fluoride from Antarctic krill samples were obtained by adding 8mL of 1:11(v/v) hydrochloric acid solution and extracting for 60 min. Under these conditions, recoveries of fluoride from Euphausia superba and Penaeus vannamei were 97.9-105.6% and 95.1-101.9%, respectively. The limit of detection was 0.01mg/kg. The method was applied to the determination of fluoride in Antarctic krill. Key words: Fluoride, Antarctic krill, Ion chromatography

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