Spectrophotometric Determination of Color Intensity of Whisky: Collaborative Study

1982 ◽  
Vol 65 (2) ◽  
pp. 224-226
Author(s):  
Duane H Strunk ◽  
Bertha M Timmel ◽  
Jack W Hamman ◽  
Arthur A Andreasen
Keyword(s):  
Standard Deviation ◽  
Spectrophotometric Determination ◽  
Coefficient Of Variation ◽  
Collaborative Study ◽  
New Method ◽  
Color Intensity ◽  
Maximum Standard Deviation ◽  
Aoac Method

Abstract A method for measuring color intensity of whisky was developed to replace the present AOAC method, which has become obsolete. The new method was collaboratively studied by 20 persons. Color intensity of whisky was measured as absorbance by a spectrophotometer, using a 1 cm cell, a bandwidth ≤10 nm, and a wavelength of 525 nm. Water was used as reference. Collaborator results appear acceptable for whisky samples that vary in color intensity from 29 to 374 CIU (absorbance X 1000 = Color Intensity Units (CIU)). The maximum standard deviation and coefficient of variation were 5.8 CIU and 6.68%, respectively. The method has been adopted official first action.

Gas Chromatographic Methods for Determination of γ-BHC in Technical Emulsifiable Concentrates and Water-Dispersible Powder Formulations and in Lindane Shampoo and Lotion: Collaborative Study

1984 ◽  
Vol 67 (4) ◽  
pp. 834-837
Author(s):  
James W Miles ◽  
Dwight L Mount ◽  
◽  
T J Beckmann ◽  
S K Carrigan ◽  
...  
Keyword(s):  
Coefficient Of Variation ◽  
Collaborative Study ◽  
Internal Standard ◽  
The Other ◽  
Water Dispersible ◽  
Coefficients Of Variation ◽  
Aoac Method ◽  
Liquid Chromatographic ◽  
Gas Chromatographic Separation

Abstract Although the gas chromatographic separation of the isomers of BHC was demonstrated two decades ago, the present AOAC method of analysis of BHC for gamma-isomer (lindane) content is based on a separation carried out on a liquid chromatographic partition column. A method of analysis has been developed that uses an OV-210 column for separation of the gamma-isomer from the other isomers and impurities in technical BHC. Di-n-propyl phthalate was chosen as an internal standard. The same system allows quantitation of lindane in lotion and shampoo after these products are extracted with ethyl acetate-isooctane (1 + 4). The analytical methods were subjected to a collaborative trial with 10 laboratories. The coefficient of variation for technical BHC was 2.83%. For the water-dispersible powder and emulsifiable concentrate, the coefficients of variation were 2.89% and 4.62%, respectively. Coefficients of variation for 1% lindane lotion and shampoo were 4.36% and 11.92%, respectively. The method has been adopted official first action.

Collaborative Study on the GLC and AOAC Methods for the Quantitative Determination of Lactic and Succinic Acids in Egg

1970 ◽  
Vol 53 (1) ◽  
pp. 28-35
Author(s):  
Walter F Staruszkiewicz
Keyword(s):  
Lactic Acid ◽  
Standard Deviation ◽  
Succinic Acid ◽  
Collaborative Study ◽  
Good Precision ◽  
Three Samples ◽  
Egg Extracts ◽  
Aoac Method ◽  
Whole Egg

Abstract Nine laboratories collaboratively studied a method for the quantitative GLC determination of lactic and succinic acids in eggs. Four of the laboratories also analyzed samples by the official AOAC method (16.037–16.042). Samples of frozen whole egg, some passable and some decomposed, were analyzed. The organic acids were extracted by the present AOAC procedures, the acids were then esterified with BF2-l-propanol, and the esters were quantitated by GLC. A collaborative report already published on the GLC determination of standard lactic and succinic acids added to egg extracts established that the method gives accurate results over a broad range of acid concentrations. The samples in the present study contained 4–30 mg lactic acid/100 g egg and 0–20 mg succinic acid/100 g egg. Each collaborator analyzed three samples in duplicate and one sample in triplicate. Using the GLC method, the standard deviation was never greater than 0.6 mg for samples containing less than 16 mg lactic acid/100 g egg, while the standard deviation was 0.2 mg for 7 mg or less succinic acid/100 g egg. The results demonstrate that the method gives good precision when it is applied to passable and to decomposed egg and the method is recommended for adoption as official first action.

Collaborative Study of Ion Selective Electrode Method for the Direct Determination of Fluoride in Feeds

1975 ◽  
Vol 58 (3) ◽  
pp. 477-481 ◽  
Author(s):  
Laszlo Torma
Keyword(s):  
Standard Deviation ◽  
Collaborative Study ◽  
Direct Determination ◽  
Ion Selective Electrode ◽  
Official Method ◽  
Selective Electrode ◽  
Standard Curve ◽  
Electrode Method ◽  
Aoac Method

Abstract A rapid and precise method for the determination of fluoride in feeds employs HC1 extraction of the sample. Acetate buffer and sodium citrate are added to control pH and ionic strength. The amount of fluoride is calculated from a standard curve after measuring the potentials of standard and sample solutions. Eight collaborators participated in the study of the method. Statistical values on 3 pairs of samples were calculated. The standard deviation, precision, coefficient of variation, and bias, respectively, were: Pair 1, 0.005071, 0.001763, 3.09, 0.0034; Pair 2, 0.037122, 0.006475, 1.82, 0.0258; Pair 3, 0.034587, 0.013021, 2.63, 0.0227. The results from the proposed method agreed favorably with the values obtained by using the official final action AOAC method, 7.089. The average and standard deviation, respectively, for individual samples by the proposed method were: Sample 3, 0.049, 0.0029; Sample 4, 0.059, 0.0021; Sample 5, 0.334, 0.0114; Sample 6, 0.341, 0.0101; Sample 7, 0.511, 0.0219; Sample 8, 0.492, 0.0237. By the official method the values were: Sample 3, 0.049, 0.0041; Sample 4, 0.058, 0.0029; Sample 5, 0.334, 0.0055; Sample 6, 0.331, 0.0082; Sample 7, 0.517, 0.0183; Sample 8, 0.499, 0.0175. The ion selective electrode method has been adopted as official first action.

Mass Loss on Drying for Instant Coffee: Collaborative Study

1980 ◽  
Vol 63 (2) ◽  
pp. 178-179
Author(s):  
William P Clinton ◽  
Paul H Manni ◽  
John M Ferry
Keyword(s):  
Standard Deviation ◽  
Mass Loss ◽  
Coefficient Of Variation ◽  
Collaborative Study ◽  
Instant Coffee ◽  
Reproducibility Standard Deviation ◽  
Repeatability Standard Deviation ◽  
Working Method

Abstract A collaborative study was undertaken to define an acceptable routine working method for determination of mass loss in instant coffee. Fourteen laboratories of 24 invited to participate submitted results. The repeatability standard deviation and coefficient of variation were 0.026 and 0.7%, respectively. The reproducibility standard deviation and coefficient of variation were 0.153 and 3.8%, respectively. The method has been adopted as official first action.

Collaborative Study of Assay for Benzthiazide and Hydrochlorothiazide in Pharmaceuticals

1972 ◽  
Vol 55 (1) ◽  
pp. 161-162
Author(s):  
F Raymond Fazzari
Keyword(s):  
Standard Deviation ◽  
Spectrophotometric Determination ◽  
Collaborative Study ◽  
Chromatographic Technique

Abstract A method for the determination of benzthiazide and hydrochlorothiazide in pharmaceuticals was collaboratively studied by 10 analysts. The method is a previously published column partition chromatographic technique with a spectrophotometric determination. The average per cent recovered and standard deviation for preparations of benzthiazide and hydrochlorothiazide were, respectively, 99.5±1.35 and 99.6±1.22. It is recommended that the method be adopted as official first action for benzthiazide, hydrochlorothiazide, and hydroflumethiazide

Collaborative Study on the Analysis of Amyl p-Dimethylaminobenzoate in Suntan Preparations by Chromatography and Ultraviolet Spectrophotometry

1970 ◽  
Vol 53 (1) ◽  
pp. 84-86
Author(s):  
Henry M. Davis
Keyword(s):  
Standard Deviation ◽  
Coefficient Of Variation ◽  
Collaborative Study ◽  
Uv Spectrophotometry ◽  
Partition Chromatography ◽  
Ultraviolet Spectrophotometry

Abstract A method for the determination of amyl p-dimethylaminobenzoate in suntan preparations was submitted for collaborative study. The sunscreen is isolated by partition chromatography and determined by UV spectrophotometry. The data of two collaborators were discarded. Results for the six collaborators show recoveries of 94-101% for samples containing from 10.2 to 23.1 mg sunscreen. The standard deviation varied from 0.18 to 0.72 and the coefficient of variation from 1.84 to 3.6%. It is recommended that the method be adopted as official first action.

Collaborative Study of a Spectrophotometric Determination of Ferric, Ferrous, and Total Iron in Drugs by Reaction with α,α′-Dipyridyl

1977 ◽  
Vol 60 (6) ◽  
pp. 1350-1354
Author(s):  
Daniel J Sullivan
Keyword(s):  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
Coefficient Of Variation ◽  
Collaborative Study ◽  
Total Iron ◽  
Average Recovery ◽  
Average Coefficient ◽  
Iron Preparation ◽  
Colorimetric Reagent

Abstract A spectrophotometric method for determining Fe2+, Fe3+, and total Fe in drugs has been developed, using α, α′-dipyridyl as the colorimetric reagent. The method is applicable to tablets, elixirs, injectables, and bulk powders. Eight collaborators analyzed a synthetic iron preparation and 7 commercial samples. For the synthetic iron preparation, the average recovery was 100.3% and the coefficient of variation was 1.02%. For 7 commercial samples, the average coefficient of variation was 1.44%. The method has been adopted as official first action.

Collaborative Study of the Food Chemicals Codex Method for the Determination of the Neutralizing Value of Sodium Aluminum Phosphate

1976 ◽  
Vol 59 (1) ◽  
pp. 26-29
Author(s):  
Douglas L Park
Keyword(s):  
Standard Deviation ◽  
Collaborative Study ◽  
Aluminum Phosphate ◽  
Aoac Method ◽  
Sodium Acid Pyrophosphate

Abstract Fifteen laboratories participated in a collaborative study to evaluate the Food Chemicals Codex method for the determination of the neutralizing value of sodium aluminum phosphate. The AOAC method for determining the neutralizing value of sodium acid pyrophosphate, sec. 8.010, was also included in the study. The precisions of the Food Chemicals Codex method, based on the between-replicate standard deviation and on one collaborator making one determination, are 1.16 and 3.66, respectively. The Food Chemicals Codex method for the determination of the neutralizing value of sodium aluminum phosphate has been adopted as official first action.

Rapid Determination of Cholesterol in Single and Multicomponent Prepared Foods

1993 ◽  
Vol 76 (4) ◽  
pp. 902-906 ◽  
Author(s):  
Sami M Al-Hasani ◽  
Jan Hlavac ◽  
Mark W Carpenter
Keyword(s):  
Rapid Method ◽  
Coefficient Of Variation ◽  
Rapid Determination ◽  
Collaborative Study ◽  
Gas Chromatograph ◽  
Vegetable Soup ◽  
Aoac Method ◽  
Solvent Use ◽  
Cholesterol Determination

Abstract A rapid method has been developed for cholesterol determination in single and multicomponent foods. The method involves alcoholic KOH saponification of the samples, extraction of the nonsaponif iable fraction with hexane, and injection of concentrated extract into the gas chromatograph without derivatizations. It has been applied to a wide variety of frozen and refrigerated foods. More than 300 samples were analyzed with a coefficient of variation (CV) ranging from 0.5 to 8.6%. The average recoveries of cholesterol from spiked oil and tomato vegetable soup samples were 100 ±1.5% and 99.7 ±1.6% and the CVs were 1.5 and 1.6%, respectively. This method reduces labor by >70%, eliminates dangerous chemicals, and minimizes solvent use, compared to the AOAC method and other methods cited in the manuscript. The method was used successfully on a wide variety of multicomponent foods. We recommend this method for collaborative study under the AOAC guidelines for method approval.

Gas-Liquid Chromatographic Method for the Analysis of Microencapsulated Diazinon Insecticide: Collaborative Study

1982 ◽  
Vol 65 (1) ◽  
pp. 115-118
Author(s):  
James J Karr ◽  
◽  
J B Audino ◽  
A A Carlstrom ◽  
L T Chenery ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Active Ingredient ◽  
Coefficient Of Variation ◽  
Collaborative Study ◽  
Gas Liquid Chromatography ◽  
Flame Ionization ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic

Abstract The determination of diazinon insecticide in Knox Out 2FM formulation was studied collaboratively by 18 laboratories. Knox Out 2FM is a flowable microencapsulated insecticide formulation containing 23 wt% active ingredient. Analytical samples are first treated by grinding in a tissue grinder and then extracted in situ with acetonitrile. This preparative step breaks the capsules and allows the active ingredient to dissolve in the solvent. Single determinations on each of 2 closely matched samples were made by flame ionization gas-liquid chromatography. The standard deviation by analysts was 0.18 wt% and the coefficient of variation was 0.76%. The combined laboratory and analyst variation gave a standard deviation of 0.59 wt% and a coefficient of variation of 2.49%. The method has been adopted official first action.

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