Collaborative Study of a Method for Sodium Lauryl Sulfate in Egg Whites

1968 ◽  
Vol 51 (3) ◽  
pp. 540-543
Author(s):  
John Wiskerchen
Keyword(s):  
Sulfuric Acid ◽  
Quantitative Determination ◽  
Sodium Lauryl Sulfate ◽  
Collaborative Study ◽  
Colorimetric Method ◽  
Egg White ◽  
Mean Deviation ◽  
Lauryl Sulfate ◽  
Benzethonium Chloride

Abstract A colorimetric method for the quantitative determination of sodium lauryl sulfate in liquid, frozen, and powdered egg white was studied by eight collaborators. Determinations were made on flake and powdered egg white at levels of 0.05, 0.1, and 0.2% (w/w) and on liquid egg white at levels of 0.006, 0.0125, and 0.0250% (w/w) sodium lauryl sulfate. The egg white is dissolved in water, and the protein is precipitated with ethanol and removed by filtration. An aliquot of the filtrate is evaporated to dryness, and the residue is dissolved in water and acidified with sulfuric acid. The sodium lauryl sulfate is complexed with Azure A, extracted into chloroform, and determined spectrophotometrically at 637 mμ. A blank determination is made on another aliquot of the filtrate by complexing the sodium lauryl sulfate with benzethonium chloride. This is a stable colorless complex. Average recoveries in the collaborative study were 98—102% with a mean deviation of 2.8—5.4%. It is recommended that the method be adopted as official, first action.

Sodium Lauryl Sulfate in Egg Whites

1967 ◽  
Vol 50 (4) ◽  
pp. 847-849
Author(s):  
John Wiskerchen
Keyword(s):  
Chloride Solution ◽  
Sodium Lauryl Sulfate ◽  
Collaborative Study ◽  
Egg White ◽  
Chloride Complex ◽  
Bromphenol Blue ◽  
Lauryl Sulfate ◽  
Benzethonium Chloride ◽  
Alkyl Sulfates

Abstract A method is given for the quantitative determination of sodium lauryl sulfate in liquid, frozen, powdered, or flake-dried egg white. The egg white is dissolved in water and the protein is precipitated with ethanol and filtered off. The filtrate is evaporated, the residue is dissolved in water, and the pH is adjusted to 5.0. Total alkyl sulfates are titrated with standard benzethonium chloride solution in the presence of chloroform with bromphenol blue indicator. Results are calculated as sodium lauryl sulfate. The formation of the bromphenol bluebenzethonium chloride complex, when excess benzethonium chloride is present, is taken as the end point. The blue-green complex is soluble in the chloroform. Overall recoveries of sodium lauryl sulfate from egg whites ranged from 94 to 100%. Collaborative study of the method is recommended.

Collaborative Study Using a ZDBT Colorimetric Method for the Determination of Copper in Alcoholic Products

1967 ◽  
Vol 50 (2) ◽  
pp. 334-338
Author(s):  
Duane H Strunk ◽  
A A Andreasen
Keyword(s):  
Sulfuric Acid ◽  
Carbon Tetrachloride ◽  
Collaborative Study ◽  
Colorimetric Method ◽  
Good Precision ◽  
Determination Of Copper

Abstract Results are given on a collaborative study in which a zinc dibenzyldithiocarbamate (ZDBT) colorimetric method is used to measure copper in alcoholic products such as high wine, spirits, gin, whisky, brandy, rum, and wine. In this method, the sample is made ca 0.SN with sulfuric acid, and carbon tetrachloride containing 0.2% ZDBT is added. The colored copper-ZDBT complex is extracted in the carbon tetrachloride and measured at 438 mμ against a similar carbon tetrachloride extract of a blank. Data show good precision, and it is recommended that the ZDBT method be adopted as official, first action.

Collaborative Study of a Colorimetric Determination of Nitrate in Tobacco

1969 ◽  
Vol 52 (4) ◽  
pp. 756-759
Author(s):  
C James Rosene
Keyword(s):  
Sulfuric Acid ◽  
Standard Deviation ◽  
Systematic Error ◽  
Collaborative Study ◽  
Colorimetric Method ◽  
Water Soluble ◽  
Colorimetric Determination ◽  
Error Standard Deviation

Abstract A colorimetric method for determining water-soluble nitrate in tobacco was studied by 14 laboratories on eight Burley and two cigar filler tobacco samples with nitrate levels of 0.5–2.4%. In the method, ground tobacco is extracted with water and filtered, and an aliquot is then treated with 2,4-xylenol in sulfuric acid; then the resulting 6-nitro-2,4-xylenol is removed by distillation and measured spectrophotometrically at 450 µm. Results show that, althoughthe precision standard deviation among laboratories is generally acceptable, the systematic error standard deviation is unacceptably high. This study will be continued.

Toxicologic Studies on Hydrocarbons. VI. A Colorimetric Method for the Determination of Kerosine in Blood

1960 ◽  
Vol 6 (4) ◽  
pp. 327-331 ◽  
Author(s):  
Horace W Gerarde ◽  
Paul Skiba
Keyword(s):  
Sulfuric Acid ◽  
Carbon Tetrachloride ◽  
Quantitative Determination ◽  
Calibration Curve ◽  
Colorimetric Method ◽  
Acid Reagent

Abstract A photoelectric colorimetric method is described for the quantitative determination of kerosine in blood. The procedure involves hemolysis of 5 ml. of the sample followed by extraction of the kerosine with carbon tetrachloride. The extract is reacted with a formaldehyde- sulfuric acid reagent to produce a characteristic color. The intensity of this color is measured photometrically, and the concentration of kerosine is determined by reference to a previously prepared calibration curve. Concentrations as low as 10 ppm can be conveniently determined.

Collaborative Study of the Quantitative Determination of Titanium Dioxide in Cheese

1973 ◽  
Vol 56 (3) ◽  
pp. 535-537 ◽  
Author(s):  
Joseph L Leone
Keyword(s):  
Hydrogen Peroxide ◽  
Titanium Dioxide ◽  
Sulfuric Acid ◽  
Quantitative Determination ◽  
Collaborative Study ◽  
Color Development ◽  
Orange Color ◽  
Colorimetric Procedure

Abstract A quantitative, colorimetric procedure for the determination of titanium dioxide has been subjected to collaborative study. The method incorporates ashing, dissolution of the ash in sulfuric acid, and color development using hydrogen peroxide. The Spectrophotometric response is compared to a standard prepared similarly. The yellow-to-orange color is quite stable in the absence of Fe. Other interferences are Ni, Cu, Co, Mb, Vd, and Cr. A collaborative study of cheese containing 0.05, 0.10, and 0.4% titanium dioxide gave favorable results. The method has been adopted as official first action.

Colorimetric Determination of Hydroxyproline as Measure of Collagen Content in Meat and Meat Products: NMKL Collaborative Study

1990 ◽  
Vol 73 (1) ◽  
pp. 54-57 ◽  
Author(s):  
Kurt Kolar
Keyword(s):  
Collaborative Study ◽  
Colorimetric Method ◽  
Meat Products ◽  
Acid Oxidation ◽  
Colorimetric Determination ◽  
Mean Values ◽  
Collaborative Studies ◽  
Freeze Dried ◽  
Analytical Result

Abstract A colorimetric method for the determination of hydroxyproline as a measure of collagen in meat and meat products has been collaboratively studied in 18 laboratories. The method includes hydrolysis with sulfuric acid, oxidation with chloramine- T, and formation of a reddish purple complex with 4- dimethylaminobenzaldehyde. Five frozen and 3 freeze-dried samples were tested, ranging in content from 0.11 to 0.88% and from 0.39 to 4.0% hydroxyproline, respectively. The mean values of 2 identical samples were 0.245 and 0.251 %. The average recovery from a spiked sample was 96.1 %. The hydroxyproline content of a known sample (a mixture of 2 samples in the ratio 5:2) was calculated to 1.42%, which agrees well with the analytical result, 1.40%. In comparison with other collaborative studies, based on the ISO analytical method, the repeatability and reproducibility of this method agree well with the other results. This method was accepted as an official NMKL method by all national Committees, and has been adopted official first action by AOAC as an NMKLAOAC method.

Enhanced peroxidase-like activity of Mo-doped ceria nanoparticles for sensitive colorimetric detection of glucose

2018 ◽  
Vol 10 (1) ◽  
pp. 76-83 ◽  
Author(s):  
Xue Jiao ◽  
Wanyi Liu ◽  
Di Wu ◽  
Wenhao Liu ◽  
Hongjie Song
Keyword(s):  
Catalytic Activity ◽  
Blood Glucose ◽  
Quantitative Determination ◽  
Colorimetric Detection ◽  
Colorimetric Method ◽  
Ceria Nanoparticles ◽  
Doped Ceria ◽  
Enzyme Mimics ◽  
Small Nanoparticles

Ultra-small nanoparticles of Mo-doped ceria (Mo/CeO2 NPs) possess enhanced peroxidase-like catalytic activity and these enzyme mimics are used here for the successful quantitative determination of blood glucose via a colorimetric method.

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