Vitreous and porcelain enamels. Determination of resistance to sulfuric acid at room temperature

1998 ◽  
Keyword(s):  
Sulfuric Acid ◽  
Room Temperature

Determination of Mercury in Biological Materials

1970 ◽  
Vol 53 (6) ◽  
pp. 1172-1175 ◽  
Author(s):  
M T Jeffus ◽  
J S Elkins ◽  
C T Kenner
Keyword(s):  
Sulfuric Acid ◽  
Standard Deviation ◽  
Nitric Acid ◽  
Biological Samples ◽  
Room Temperature ◽  
Gold Foil ◽  
Average Recovery ◽  
Average Value ◽  
The Difference

Abstract Mercury in biological samples is determined by digestion in nitric acid, sulfuric acid, and permanganate, followed by reduction and aeration for measurement by atomic absorption at room temperature. The average recovery is 95.8% with a standard deviation of 13.3%. The standard deviation, calculated from the difference between duplicates of 23 samples, is 0.063 μg mercury, which represents 9.4% of the average value of the samples. The method is simple and requires approximately 4 hr for completion. Mercury can be confirmed by adsorption on gold foil after maximum absorbance has been obtained during aeration.

Collaborative Study of the Automated Determination of Nitrogen in Meat Products

1973 ◽  
Vol 56 (1) ◽  
pp. 31-35 ◽  
Author(s):  
Walter M Gantenbein
Keyword(s):  
Sulfuric Acid ◽  
Standard Deviation ◽  
Room Temperature ◽  
Collaborative Study ◽  
Meat Products ◽  
Average Standard Deviation ◽  
Colorimetric Measurement ◽  
Average Coefficient ◽  
Automated Determination

Abstract A modification of a previously reported method for nitrogen in meat products was subjected to collaborative study. Samples were dissolved in 1+1 sulfuric acid, cooled to room temperature, and presented to an Auto-Analyzer system. Digestion, dilution, and colorimetric measurement of nitrogen content were performed automatically. Seven collaborators participated in the study, analyzing 8 different samples in duplicate. Results of the study were satisfactory, with an average range of 0.95% protein, average standard deviation of ±0.39, and average coefficient of variation of 2.44%. The method has been found applicable to meat and meat products containing 0.8–4.0% nitrogen (5.0–25.0% protein).

Simple Colorimetric Method for Determination of Pyridoxine Hydrochloride (Vitamin B6) in Pharmaceuticals

1983 ◽  
Vol 66 (1) ◽  
pp. 158-160
Author(s):  
Ramesh T Sane ◽  
Vipul J Doshi ◽  
Sanjay K Joshi
Keyword(s):  
Aqueous Solution ◽  
Sulfuric Acid ◽  
Vitamin B6 ◽  
Trichloroacetic Acid ◽  
Room Temperature ◽  
Colorimetric Method ◽  
Thiamine Hydrochloride ◽  
Pyridoxine Hydrochloride ◽  
Statistical Validation

Abstract A simple colorimetric method is described for the determination of pyridoxine hydrochloride (vitamin B6). The method is based on the measurement of an orange species formed when pyridoxine hydrochloride is treated with diazotized dapsone and sulfanilamide in a mixture of trichloroacetic acid and sulfuric acid at room temperature, followed by treatment with an aqueous solution of sodium carbonate. Compounds such as thiamine hydrochloride, cyanocobalamin, and common excipients such as starch and talc which are present in various formulations with pyridoxine hydrochloride do not interfere in the reaction. Statistical validation showed that the method was highly precise and accurate. Results agree well with those obtained by other methods reported in the literature.

scholarly journals Leaching of Manganese from Marine Nodules at Room Temperature with the Use of Sulfuric Acid and the Addition of Tailings

Minerals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 289 ◽  
Author(s):  
Norman Toro ◽  
Manuel Saldaña ◽  
Jonathan Castillo ◽  
Freddy Higuera ◽  
Roxana Acosta
Keyword(s):  
Particle Size ◽  
Sulfuric Acid ◽  
Room Temperature ◽  
Sulfuric Acid Concentration ◽  
Future Research ◽  
Independent Variables ◽  
Series Of Experiments ◽  
Optimization Methodology ◽  
Cost Efficient

Based on the results obtained from a previous study investigating the dissolution of Mn from marine nodules with the use of sulfuric acid and foundry slag, a second series of experiments was carried out using tailings produced from slag flotation. The proposed approach takes advantage of the Fe present in magnetite contained in these tailings and is believed to be cost-efficient. The surface optimization methodology was used to evaluate the independent variables of time, particle size, and sulfuric acid concentration in the Mn solution. Other tests evaluated the effect of agitation speed and the MnO2/Fe2O3 ratio in an acid medium. The highest Mn extraction rate of 77% was obtained with an MnO2/Fe2O3 ratio of 1/2 concentration of 1 mol/L of H2SO4, particle size of −47 + 38 μm, and 40 min of leaching. It is concluded that higher rates of Mn extraction were obtained when tailings instead of slag were used, while future research needs to focus on determination of the optimum Fe2O3/MnO2 ratio to improve dissolution of Mn from marine nodules.

Simple fluorometric determination of aldosterone in urine without use of isotopes or chromatography.

1976 ◽  
Vol 22 (3) ◽  
pp. 369-372 ◽  
Author(s):  
W R Whigham
Keyword(s):  
Sulfuric Acid ◽  
Carboxylic Acid ◽  
Acid Derivative ◽  
Room Temperature ◽  
Fluorometric Determination ◽  
Neutral Compounds ◽  
Acidic Compounds ◽  
Nonpolar Organic ◽  
Carboxylic Acid Derivative

Abstract Aldosterone 18-glucuronide in urine is hydrolyzed by adjusting the pH to 1.0 and allowing the mixture to stand overnight at room temperature. The free aldosterone is then extracted into dichloromethane, which is washed with carbonate to remove acidic compounds and evaporated. The residue is partitioned between a nonpolar organic phase and an aqueous phase, and the aldosterone oxidized to the 13-carboxylic acid derivative with Benedict's qualitative glucose reagent. Neutral compounds are extracted from this oxidation mixture with dichloromethane at pH 7.5, the mixture is acidified, and the oxidized aldosterone extracted into dichloromethane. After washing with pH 3.5 buffer, this extract is evaporated and the oxidized aldosterone determined fluorometrically via a two-stage reaction with sulfuric acid/water (85/15 by vol) and methanol containing ferric chloride.

Determination of Chlorinated Pesticide Residues in Foods. II. Potassium Permanganate Oxidation for Cleanup of Some Vegetable Extracts

1979 ◽  
Vol 62 (3) ◽  
pp. 685-688
Author(s):  
Takashi Suzuki ◽  
Kiyoshi Ishikawa ◽  
Nobutoshi Sato ◽  
Kei-Ichi Sakai
Keyword(s):  
Sulfuric Acid ◽  
Potassium Permanganate ◽  
Pesticide Residues ◽  
Room Temperature ◽  
Test Tube ◽  
Chlorinated Pesticides ◽  
Dilute Sulfuric Acid ◽  
Radish Root ◽  
Hexane Phase

Abstract A potassium permanganate-dilute sulfuric acid KMnO4/dilute H2SO4 oxidation procedure was developed to supplement Florisil cleanup of some vegetable extracts. Following sample preparation and Florisil cleanup, a reaction mixture of the n-hexane eluate from the Florisil cleanup, 4% KMnO4, and 40% H2SO4 (l+l+l) was shaken in a test tube 2 min at room temperature and then centrifuged. The n-hexane phase was washed with 2 mL 0.1N NaOH and analyzed by GLC. Twelve chlorinated pesticides were completely recovered in the n-hexane phase. Aldrin was not recovered because its extreme instability caused it to decompose even in neutral solutions. Chlorinated pesticide residues in onion, garlic, carrot, and radish root were easily analyzed by the application of this oxidation procedure.

Interactions Between Al and Cr Thin Films

1976 ◽  
Vol 34 ◽  
pp. 638-639
Author(s):  
R. M. Anderson ◽  
T. M. Reith ◽  
M. J. Sullivan ◽  
E. K. Brandis
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Vacuum System ◽  
Processing Temperature ◽  
Diffusion Couples ◽  
Electronic Circuits ◽  
Intermetallic Formation ◽  
Si Substrates ◽  
Aluminum Silicon

Thin films of aluminum or aluminum-silicon can be used in conjunction with thin films of chromium in integrated electronic circuits. For some applications, these films exhibit undesirable reactions; in particular, intermetallic formation below 500 C must be inhibited or prevented. The Al films, being the principal current carriers in interconnective metal applications, are usually much thicker than the Cr; so one might expect Al-rich intermetallics to form when the processing temperature goes out of control. Unfortunately, the JCPDS and the literature do not contain enough data on the Al-rich phases CrAl7 and Cr2Al11, and the determination of these data was a secondary aim of this work.To define a matrix of Cr-Al diffusion couples, Cr-Al films were deposited with two sets of variables: Al or Al-Si, and broken vacuum or single pumpdown. All films were deposited on 2-1/4-inch thermally oxidized Si substrates. A 500-Å layer of Cr was deposited at 120 Å/min on substrates at room temperature, in a vacuum system that had been pumped to 2 x 10-6 Torr. Then, with or without vacuum break, a 1000-Å layer of Al or Al-Si was deposited at 35 Å/s, with the substrates still at room temperature.

STEM and ELS Observation of Early Oxide Formation on the Surface of Cr Thin Films

1980 ◽  
Vol 38 ◽  
pp. 412-413
Author(s):  
Fumio Watari ◽  
J. M. Cowley
Keyword(s):  
Thin Films ◽  
Optical System ◽  
Room Temperature ◽  
Oxide Formation ◽  
Initial Nucleation ◽  
Diffraction Patterns ◽  
Relationship Of ◽  
Multiple Twinning ◽  
Moderately High Temperature

STEM coupled with the optical system was used for the investigation of the early oxidation on the surface of Cr. Cr thin films (30 – 1000Å) were prepared by evaporation onto the polished or air-cleaved NaCl substrates at room temperature and 45°C in a vacuum of 10−6 Torr with an evaporation speed 0.3Å/sec. Rather thick specimens (200 – 1000Å) with various preferred orientations were used for the investigation of the oxidation at moderately high temperature (600 − 1100°C). Selected area diffraction patterns in these specimens are usually very much complicated by the existence of the different kinds of oxides and their multiple twinning. The determination of the epitaxial orientation relationship of the oxides formed on the Cr surface was made possible by intensive use of the optical system and microdiffraction techniques. Prior to the formation of the known rhombohedral Cr2O3, a thin spinel oxide, probably analogous to γ -Al203 or γ -Fe203, was formed. Fig. 1a shows the distinct epitaxial growth of the spinel (001) as well as the rhombohedral (125) on the well-oriented Cr(001) surface. In the case of the Cr specimen with the (001) preferred orientation (Fig. 1b), the rings explainable by spinel structure appeared as well as the well defined epitaxial spots of the spinel (001). The microdif fraction from 20A areas (Fig. 2a) clearly shows the same pattern as Fig. Ia with the weaker oxide spots among the more intense Cr spots, indicating that the thickness of the oxide is much less than that of Cr. The rhombohedral Cr2O3 was nucleated preferably at the Cr(011) sites provided by the polycrystalline nature of the present specimens with the relation Cr2O3 (001)//Cr(011), and by further oxidation it grew into full coverage of the rest of the Cr surface with the orientation determined by the initial nucleation.

A New Method for Direct Determination of the Recoilless Fraction with Application to Magnetic Nanoparticles

2002 ◽  
Vol 721 ◽  
Author(s):  
Monica Sorescu
Keyword(s):  
Room Temperature ◽  
Average Particle Size ◽  
Direct Determination ◽  
Average Particle ◽  
Lattice Method ◽  
Recoilless Fraction ◽  
Single Room ◽  
Magnetite Particles ◽  
Physical Mixtures

AbstractWe propose a two-lattice method for direct determination of the recoilless fraction using a single room-temperature transmission Mössbauer measurement. The method is first demonstrated for the case of iron and metallic glass two-foil system and is next generalized for the case of physical mixtures of two powders. We further apply this method to determine the recoilless fraction of hematite and magnetite particles. Finally, we provide direct measurement of the recoilless fraction in nanohematite and nanomagnetite with an average particle size of 19 nm.

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