Chromatographic Procedure for Determination of Reserpine in Tablets. II. Collaborative Study

1969 ◽  
Vol 52 (1) ◽  
pp. 113-115
Author(s):  
Susan Barkan
Keyword(s):  
Quantitative Determination ◽  
Collaborative Study ◽  
Chromatographic Column ◽  
Colorimetric Analysis ◽  
Acid Base ◽  
Water Layers ◽  
Suitable Amount ◽  
Chromatographic Procedure ◽  
Tablet Formulations

Abstract A method is described for the quantitative determination of reserpine in tablet formulations. A suitable amount of tablet material is triturated with dimethylsulfoxide (DMSO), incorporated onto Celite, and transferred to a chromatographic column containing acid, base, and water layers. The reserpine is eluted with chloroform and quantitated spectrophotometrically. Duplicate results from 16 collaborators averaged 100.7% recovery as determined by UV, 98.8% recovery determined by colorimetric analysis. The method is recommended for adoption as official first action.

Gas Chromatographic Determination of Residual Hexane in Modified Hop Extract

1972 ◽  
Vol 55 (6) ◽  
pp. 1226-1227
Author(s):  
Mark A Litchman ◽  
Lewis A Turano ◽  
Ronald P Upton
Keyword(s):  
Liquid Chromatography ◽  
Quantitative Determination ◽  
Chromatographic Determination ◽  
Methanol Solution ◽  
Chromatographic Column ◽  
Gas Liquid Chromatography ◽  
Porapak Q ◽  
Residual Hexane ◽  
Head Space

Abstract A method is described for the quantitative determination of hexane in modified hop extract by head-space gas-liquid chromatography. A sample of extract is weighed into a serum vial and water-methanol solution is added. The vial is sealed tightly and heated 1 hr in a 70°C bath. A sample of the head-space gas over the solution is injected onto a Porapak Q gas chromatographic column for determination. Recovery of 2–29 ppm hexane added to potassium isohumulone was 95.5–114.8%. The method may be applicable to other hop extracts.

Determination of Hydroxybenzoates and Benzoates in Foods

1968 ◽  
Vol 51 (4) ◽  
pp. 876-877
Author(s):  
M H Lewis
Keyword(s):  
Quantitative Determination ◽  
Steam Distillation ◽  
Uv Spectroscopy ◽  
Collaborative Study ◽  
Solid Foods

Abstract A successful collaborative study was made on the determination of benzoates in solid foods, using the official, first action method for benzoates in liquid and semisolid foods. The method combines steam distillation, TLC, and UV spectroscopy. Recovery data ranged from 94 to 120%. An attempt to separate the parabens by GLC was successful but further work is needed for the quantitative determination of these compounds.

GLC Determination of the Optical Isomers of Amphetamine

1970 ◽  
Vol 53 (1) ◽  
pp. 113-115
Author(s):  
Clyde E Wells
Keyword(s):  
Quantitative Determination ◽  
Calibration Curve ◽  
Collaborative Study ◽  
Isomeric Ratio ◽  
Dosage Forms ◽  
Optical Isomers ◽  
Standard Calibration ◽  
Tablet Dosage

Abstract A method is described for the quantitative determination of the ratio of d- and l-amphetamine stereoisomers by GLC. A derivative formed with N-trifluoroacetyl-(l)-prolyl chloride is chromatographed and the isomeric ratio is read from a standard calibration curve. The method is applicable to crystalline salts of amphetamine and to commercial tablet dosage forms. It is recommended that this method be subjected to collaborative study.

Collaborative Study of a Gas Chromatographic Determination of Methylene Chloride, Ethylene Dichloride, and Trichloroethylene Residues in Spice Oleoresins

1968 ◽  
Vol 51 (4) ◽  
pp. 825-828
Author(s):  
Laura A Roberts
Keyword(s):  
Methylene Chloride ◽  
Collaborative Study ◽  
Chromatographic Determination ◽  
Chromatographic Column ◽  
Ethylene Dichloride ◽  
Gas Chromatograph ◽  
Porapak Q ◽  
Relative Retention ◽  
Solvent Residues

Abstract A method for the gas chromatographic determination of methylene chloride, ethylene dichloride, and trichloroethylene residues in spice oleoresins was studied collaboratively. The method employs a microcoulometric gas chromatograph fitted with a Porapak Q column and is based on the volatility of the solvent residues, their relative retention times on a polyaromatic bead chromatographic column, and their detectability by a halide-specific microcoulometric method. Recoveries were adequate when the method was closely followed; recoveries were erratic when collaborators deviated from the method. Further study is recommended.

Gas Chromatographic Determination of Cadaverine, Putrescine, and Histamine in Foods

1981 ◽  
Vol 64 (3) ◽  
pp. 584-591 ◽  
Author(s):  
Walter F Staruszkiewicz ◽  
John F Bond
Keyword(s):  
Quantitative Determination ◽  
Ethyl Acetate ◽  
Electron Capture ◽  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Alumina Column ◽  
Fishery Products ◽  
Specific Detector

Abstract A GLC procedure for the quantitative determination of the diamines putrescine and cadaverine has been developed, using their perfluoropropionyl derivatives. The amines were extracted from foods with methanol; an internal standard, hexanediamine, was added and a dry residue of their hydrochloride salts was prepared. The salts were derivatized with perfluoropropionic anhydride by heating for 30 min at 50°C. The reaction mixture was separated on an alumina column to remove excess reagent, and the derivatives were eluted with a solution of 30% ethyl acetate in toluene. GLC separations were performed on a 3% OV-225 column held at 180°C. The retention times were 4.3,5.7, and 7.0 min for the derivatives for putrescine, cadaverine, and the internal standard, respectively. Less than 1 μg diamine/g tissue could be quantitated, using either an electron capture detector or a nitrogen-specific detector. The procedure was applied to cheese and a variety of fishery products. An increase in the diamines correlated with the presence of decomposition in some of the products. A collaborative study of the method is planned.

Quantitative Determination of FD&C Colors in Foods

1975 ◽  
Vol 58 (2) ◽  
pp. 278-282
Author(s):  
Charles Graichen
Keyword(s):  
Quantitative Determination ◽  
Anion Exchange ◽  
Salt Solution ◽  
Exchange Resin ◽  
Anion Exchange Resin ◽  
Collaborative Study ◽  
Chromatographic Technique ◽  
Different Color ◽  
Selection Of

Abstract A published procedure using Amberlite LA-2 (a liquid anion exchange resin) solutions to extract colors from food and the salt solution cellulose chromatographic technique to separate colors from each other were updated and submitted to collaborative study. Three batches of cookies and 4 purchased products were analyzed by 13 collaborators. The 3 batches of cookies contained different color mixtures requiring the selection of various procedures. The 4 purchased products were selected principally to include a variety of foods. Some results were partially deficient. The deficiencies reflect certain inadequacies in the directions as written rather than basic flaws in the method. Some improvements were suggested by the collaborators. The Associate Referee recommends that the method be further revised to correct the present inadequacies and to include some improvements, and that the revised method be submitted to another collaborative study.

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.

Quantitative Determination and Confirmation of Low Levels of Diethylstilbestrol in Feeds

1972 ◽  
Vol 55 (6) ◽  
pp. 1345-1353
Author(s):  
Marshall T Jeffus ◽  
Charles T Kenner
Keyword(s):  
Thin Layer ◽  
Quantitative Determination ◽  
Official Method ◽  
Trans Isomers ◽  
Cis And Trans Isomers ◽  
Before And After ◽  
Chromatographic Procedure ◽  
Low Levels ◽  
Cis And Trans

Abstract A method for the determination of diethylstibestrol in feeds, which is based on official first action method 38.048–38.051, is proposed. Interfering feed extractives are removed by using a tripotassium phosphate-Celite column prior to measurement at 415 nm before and after irradiation. Recoveries of equilibrated standards added to Soxhlet extracts of several samples averaged 94.3% compared to 86.3% by the official method. The background absorbance at 415 nm obtained by using the proposed method was approximately 6% of the background by the official method for solutions containing equivalent amounts of sample. A thin layer chromatographic method is also included for the confirmation and identification of the cis and trans isomers of the drug. The proposed method has been found satisfactory for the quantitative determination of 0.55–44 ppm diethylstilbestrol and the thin layer chromatographic procedure can detect as little as 0.07 ppm.

Collaborative Study of a Zincon Ion Exchange Method for the Quantitative Determination of Zinc in Fertilizers

1971 ◽  
Vol 54 (4) ◽  
pp. 790-795
Author(s):  
C E Jones ◽  
L E Pracht
Keyword(s):  
Ion Exchange ◽  
Quantitative Determination ◽  
Atomic Absorption ◽  
Reference Data ◽  
Collaborative Study ◽  
Present Form ◽  
Exchange Method ◽  
Ion Exchange Method ◽  
Absorption Measurements

Abstract This collaborative study represents an attempt to validate the ion exchange zincon method for the quantitative determination of zinc in fertilizers. The values of the standard deviations Sd, Sr, and Sb and the results of the F- and t-tests are presented as an estimate of the precision, accuracy, and dependability. Atomic absorption measurements were also made and provided reference data for evaluation purposes. In its present form, the method falls short of expectations as an alternative wet approach to the dithizone method. It is recommended that the methods for determining zinc in fertilizers be studied further.

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