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 Using Atomic Absorption Spectrophotometry for the Determination of Copper in Alcoholic Products

1967 ◽  
Vol 50 (2) ◽  
pp. 338-339
Author(s):  
Duane H Strunk ◽  
A A Andreasen
Keyword(s):  
Atomic Absorption ◽  
Spectrophotometric Method ◽  
Collaborative Study ◽  
Atomic Absorption Spectrophotometry ◽  
Good Precision ◽  
Absorption Method ◽  
Standard Curve ◽  
Absorption Spectrophotometry ◽  
Determination Of Copper

Abstract A collaborative study was conducted on the 'atomic absorption spectrophotometric method for measuring the concentration of copper in alcoholic products. In this method, the samples are aspirated directly into the burner of the instrument, and the absorhance values are converted to ppm copper by reference to a standard curve. Data show good precision and are comparable to those obtained by the ZDBT method. It is recommended that the atomic absorption method be adopted as official, first action.

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.

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.

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.

Collaborative Study of the Gas-Liquid Chromatographic Method for Determination of Stereochemical Composition of Amphetamine

1972 ◽  
Vol 55 (1) ◽  
pp. 146-148
Author(s):  
Clyde E Wells
Keyword(s):  
Column Chromatography ◽  
Chromatographic Method ◽  
Collaborative Study ◽  
Good Precision ◽  
Liquid Chromatographic Method ◽  
Precision And Accuracy ◽  
Standard Deviations ◽  
Liquid Chromatographic ◽  
Amphetamine Sulfate

Abstract Eight laboratories collaboratively studied a method for the quantitative GLC determination of d- and l-amphetamine in tablets. The drugs are separated from tablet excipients by column chromatography and reacted with Ntrifluoroacetyl-( 0-prolyl chloride, and the resulting derivatives are analyzed by GLC. The samples consisted of commercial d-amphetamine sulfate tablets (with and without butabarbital), dl-amphetamine sulfate tablets, and a mixed d- and l-amphetamine sulfate standard. Recoveries were acceptable, and the standard deviations never exceeded 0.64%. The results demonstrate that the method gives good precision and accuracy, and the method is recommended for adoption as official first action.

Sulfuric Acid/Hydrogen Peroxide Digestion and Colorimetric Determination of Phosphorus in Meat and Meat Products: Collaborative Study

1991 ◽  
Vol 74 (1) ◽  
pp. 22-26 ◽  
Author(s):  
David K Christians ◽  
Thomas G Aspelund ◽  
Scott V Brayton ◽  
Larry L Roberts
Keyword(s):  
Hydrogen Peroxide ◽  
Sulfuric Acid ◽  
Collaborative Study ◽  
Meat Products ◽  
Colorimetric Determination ◽  
Pork Sausage ◽  
Relative Standard ◽  
Significant Difference ◽  
Standard Deviations

Abstract Seven laboratories participated In a collaborative study of a method for determination of phosphorus in meat and meat products. Samples are digested In sulfuric acid and hydrogen peroxide; digestion Is complete In approximately 10 mln. Phosphorus Is determined by colorimetric analysis of a dilute aliquot of the sample digest. The collaborators analyzed 3 sets of blind duplicate samples from each of 6 classes of meat (U.S. Department of Agriculture classifications): smoked ham, water-added ham, canned ham, pork sausage, cooked sausage, and hamburger. The calibration curve was linear over the range of standard solutions prepared (phosphorus levels from 0.05 to 1.00%); levels in the collaborative study samples ranged from 0.10 to 0.30%. Standard deviations for repeatability (sr) and reproducibility (sR) ranged from 0.004 to 0.012 and 0.007 to 0.014, respectively. Corresponding relative standard deviations (RSDr and RSDR, respectively) ranged from 1.70 to 7.28% and 3.50 to 9.87%. Six laboratories analyzed samples by both the proposed method and AOAC method 24.016 (14th Ed.). One laboratory reported results by the proposed method only. Statistical evaluations Indicated no significant difference between the 2 methods. The method has been adopted official first action by AOAC.

scholarly journals Automatic simultaneous determination of copper and lead in biological samples by flow injection/stripping voltammetric analysis

1993 ◽  
Vol 15 (4) ◽  
pp. 121-125 ◽  
Author(s):  
Andrés Izquierdo ◽  
M. D. Luque de Castro ◽  
Miguel Valcárcel
Keyword(s):  
Simultaneous Determination ◽  
Flow Injection ◽  
Certified Reference Materials ◽  
Stripping Voltammetry ◽  
Bovine Liver ◽  
Good Precision ◽  
Voltammetric Analysis ◽  
Statistical Studies ◽  
Determination Of Copper

An automatic-continuous method for the simultaneous determination of copper and lead based on flow injection analysis (FIA) and stripping voltammetry (SV) is proposed. The method affords the determination of the analytes at the ng/ml level (linear ranges 0.64 to 64.0 ng/ml and 2.1 to 62.2 ng/ml for copper and lead, respectively) with good precision (r.s.d. values smaller than 4%). The selectivity of SV allows the method to be applied to the determination of these analytes in bovine liver fresh samples and certified reference materials from the National Institute for Standards and Technology and the Community Bureau of Reference. The performance of the method was assessed by repeatability and validation statistical studies.

Collaborative Study of the Ion-Pair Column Partition Method for the Determination of Phenylephrine.HC1 in Drug Formulations

1970 ◽  
Vol 53 (1) ◽  
pp. 120-122
Author(s):  
Michel Margosis
Keyword(s):  
Collaborative Study ◽  
Colorimetric Method ◽  
Ion Pair ◽  
Confidence Limits ◽  
Drug Formulations ◽  
Three Solutions ◽  
The Mean ◽  
Partition Method ◽  
Collaborative Evaluation

Abstract Three solutions containing varying amounts of phenylephrine.HC1 were subjected to a collaborative evaluation of the ion-pair column partition method of Levine and Doyle. Results submitted by 20 collaborators were evaluated statistically. Recoveries averaged 99.0, 100.8, and 103.5% with 95% confidence limits of the mean of ±0.71, ±0.53, and ±0.85%, respectively. The method is recommended for adoption as official first action. The colorimetric method approved last year is recommended for adoption as official final action.

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