Collaborative Study of Acid-Detergent Fiber and Lignin

1973 ◽  
Vol 56 (4) ◽  
pp. 781-784 ◽  
Author(s):  
Peter J Van Soest
Keyword(s):  
Wheat Straw ◽  
Soybean Meal ◽  
Standard Error ◽  
Coefficient Of Variation ◽  
Collaborative Study ◽  
Barley Straw ◽  
Acid Detergent Fiber ◽  
Collaborative Test ◽  
Definition Of

Abstract A second collaborative study on acid-detergent fiber and lignin has been completed involving 10 laboratories and 6 samples including timothy, alfalfa, soybean meal, barley straw, orchardgrass, and wheat straw. Results from 7 laboratories appeared normal according to the Youden collaborative test and yielded a mean duplicate error of 0.40±0.31, a standard error between laboratories of 0.40, and a coefficient of variation of 1.02%. The duplicate error for lignin was 0.23±0.31, the standard error between laboratories, 0.28, and the coefficient of variation, 4.26%. Results indicate problems with filtering, handling fritted glass crucibles in a uniform weighing procedure, and reliably preparing asbestos used in the preparation of lignin. Modifications of the previously published method include reduction of sample size to 1 g, elimination of the use of decalin, rigorous definition of filtration and weighing procedures, use of P2O5 or Mg(ClO4)2 as desiccant, and determination of a lignin blank. Problems in filtration can be overcome by not using more vacuum than is necessary, making all additions with vacuum off, and allowing 15–30 sec settling before applying suction. The modified acid-detergent fiber and lignin method has been adopted as official first action.

Determination of Natamycin in Cheese and Cheese Rind: Interlaboratory Collaborative Study

1987 ◽  
Vol 70 (6) ◽  
pp. 949-954
Author(s):  
Willem G Deruig
Keyword(s):  
Coefficient Of Variation ◽  
Collaborative Study ◽  
Spectrometric Method ◽  
Ultraviolet Detection ◽  
Collaborative Test ◽  
Low Levels ◽  
Liquid Chromatographic

Abstract A collaborative test on the determination of natamycin in cheese and cheese rind was conducted. Participants were from 37 laboratories in 13 countries. Eight samples, consisting of 4 duplicates, were investigated by a spectrometric method and a liquid chromatographic (LC) method. The spectrometric method gave good results (coefficient of variation [CV] = 12%) and the LC method with ultraviolet detection gave reasonable results (CV = 25%) for levels down to 15 mg/ kg (0.9 mg/dm2). For very low levels, a preconcentration step is necessary, but even then quantitation is poor (CV = 35-37%) for both methods at 1.7 mg/kg, although the presence of natamycin can be detected qualitatively. For a level of 0.3 mg/kg, quantitation is poor (CV = 39%) for the LC method and impossible (CV = 60%) for the spectrometric method.

scholarly journals Collaborative study to evaluate the indigestible neutral detergent fiber and indigestible acid detergent fiber contents in feeds by in situ procedure

2016 ◽  
Vol 37 (4Supl1) ◽  
pp. 2589
Author(s):  
Marjorrie Augusto de Souza ◽  
Edenio Detmann ◽  
Gabriel Cipriano Rocha ◽  
Marcia De Oliveira Franco ◽  
Erick Darlisson Batista ◽  
...  
Keyword(s):  
Soybean Meal ◽  
Collaborative Study ◽  
Neutral Detergent Fiber ◽  
Acid Detergent Fiber ◽  
Animal Science ◽  
Percentage Points ◽  
Individual Evaluation ◽  
The Individual ◽  
Standardization Of Procedures

The objective of this collaborative study was to evaluate the indigestible neutral detergent fiber (iNDF) and indigestible acid detergent fiber (iADF) content in feeds in six laboratories from institutions linked to the National Institute of Science and Technology in Animal Science (INCT-CA). Six feeds were evaluated: signal grass hay, sugarcane, corn silage, soybean meal, corn and citrus pulp. Estimated levels of iNDF and iADF proved to be dependent on the laboratory in which the analysis was performed. It was found that differences between laboratories ranged from 2.40 percentage points for soybean meal to 8.05 percentage points for sugarcane for iNDF analysis and from 1.79 percentage points for corn to 10.06 percentage points for hay for iADF analysis. It was observed that the individual evaluation of each material, the total random variation of the results between laboratories ranged from 88.75 to 96.77% and 88.75 to 98.40% for iNDF and iADF analysis, respectively. The iNDF and iADF levels are dependent on the interaction effect between the evaluated material and laboratory and have low reproducibility; this may be a consequence of the differences between the methods practiced by each laboratory, demonstrating lack of standardization of procedures used by the laboratories.

Liquid Chromatographic Determination of Methiocarb in Technical and Formulated Products: Collaborative Study

1984 ◽  
Vol 67 (3) ◽  
pp. 492-493
Author(s):  
Stephen C Slahck ◽  
◽  
A A Carlstrom ◽  
L T Chenery ◽  
N D Ellis ◽  
...  
Keyword(s):  
Coefficient Of Variation ◽  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Reverse Phase ◽  
Reverse Phase Chromatography ◽  
Wettable Powder ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract An LC method for the determination of methiocarb in methiocarb technical and formulated products has been subjected to a collaborative study with 9 participating collaborators. Formulations are extracted with acetonitrile and analyzed by reverse phase chromatography, with acetophenone as an internal standard. Collaborators were furnished samples of technical, 75% wettable powder, 75% seed treater, 75% concentrate, and 50% hopper box treater. Coefficient of variation values obtained on the 5 samples were 0.71, 0.83, 0.62, 1.57, and 0.82%, respectively. The method has been adopted official first action.

Diagnostic Data Evaluation. Part II. Collaborative Study Evaluation: Coefficient of Variation Considered To Be A Constant

1990 ◽  
Vol 73 (2) ◽  
pp. 235-241
Author(s):  
Anthony J Malanoski
Keyword(s):  
Coefficient Of Variation ◽  
Collaborative Study ◽  
Performance Standards ◽  
Data Evaluation ◽  
Diagnostic Data ◽  
Study Evaluation

Abstract The principles described in Part I were used to determine standards of performance for the method and for analysts from a collaborative study of the determination of nitrosopyrrolidine (NPYR). Performance standards for the method were 10.4% RSDa, 9.2% for RSDo, and 14.2% for RSDx.

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.

Determination of Zearalenone in Corn: Collaborative Study

1976 ◽  
Vol 59 (3) ◽  
pp. 666-670
Author(s):  
Odette L Shotwell ◽  
Marion L Goulden ◽  
Glenn A Bennett
Keyword(s):  
Statistical Analysis ◽  
Thin Layer ◽  
Coefficient Of Variation ◽  
Collaborative Study ◽  
Corn Sample ◽  
Yellow Corn ◽  
Coefficients Of Variation ◽  
The Mean

Abstract Corn samples spiked at levels of 100, 300, 1000, and 2000 μg zearalenone/kg were sent to 22 collaborators for analysis by the Eppley method. All samples were yellow corn except one white corn sample spiked at 2000 μg/kg. Results from 16 collaborators were statistically analyzed. Only 4 of 16 collaborators detected zearalenone in the sample containing 100 μg/kg, but 11 detected the toxin in the sample containing 300 μg/kg. Average recoveries from all samples were 129% at 300 μg/kg, 101% at 1000 μg/kg, and 88% at 2000 μg/kg. The between-laboratory coefficients of variation were 53.0% at 300 μg/kg, 38.2% at 1000 μg/kg, and 27.0% at 2000 μg/kg. Five naturally contaminated corn samples, one in triplicate, were also provided. The mean level of zearalenone in the naturally contaminated samples ranged from 431 to 7622 μg/kg. The mean coefficient of variation for all samples was 40.5%. Two collaborators measured quantities of zearalenone on thin layer chromatographic plates densitometrically. Their results were not included in the statistical analysis, but the results indicated that densitometric measurement, given proper dilutions of solutions, could be used. The method has been adopted as official first action.

Collaborative Study for the Determination of Nequinate in Feeds

1971 ◽  
Vol 54 (1) ◽  
pp. 69-71
Author(s):  
Phillip L Cox
Keyword(s):  
Formic Acid ◽  
Coefficient Of Variation ◽  
Collaborative Study ◽  
Methanesulfonic Acid ◽  
Average Coefficient

Abstract A collaborative study has been conducted on a previously reported method for the determination of nequinate in feeds. The drug is extracted from feed with 1% formic acid in chloroform and measured spectrofluorometrically after dilution with chloroform and the addition of methanesulfonic acid. Eight collaborators participated in the study, analyzing 7 different feeds. The average coefficient of variation for the study was 5.3%. The method is recommended for adoption as official first action.

scholarly journals Gas Chromatographic Determination of Alachlor in Microencapsulated Formulations: Mini-Collaborative Study

1987 ◽  
Vol 70 (6) ◽  
pp. 1056-1058
Author(s):  
David F Tomkins
Keyword(s):  
Coefficient Of Variation ◽  
Chromatographic Method ◽  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Chromatographic Column ◽  
Data Points ◽  
Gas Chromatographic Method ◽  
Isothermal Gas

Abstract An isothermal gas chromatographic method for measuring alachlor in Micro-Tech® (microencapsulated) formulations was tested by 5 collaborators. The samples were prepared in acetone, and alachlor was determined using a gas chromatographic column of 10% SP- 2250 on 100-120 mesh Supelcoport. Di-n-pentylphthalate was used as the internal standard. Collaborators made single determinations on 5 samples distributed as blind duplicates. The mini-collaborative study generated 47 data points. The coefficient of variation (CV„- pooled) was 1.35%, and CVx-pooled was 0.73%. The method was simple to use and did not reveal any interferences in samples tested. The method has been adopted official first action as an AOACCIPAC method.

Collaborative Study of a Gas-Liquid Chromatographic Method for the Determination of Simazine

1976 ◽  
Vol 59 (4) ◽  
pp. 758-760
Author(s):  
Arthur H Hofberg ◽  
Lee C Heinrichs ◽  
Gene A Gentry
Keyword(s):  
Coefficient Of Variation ◽  
Chromatographic Method ◽  
Collaborative Study ◽  
Internal Standard ◽  
Matched Pair ◽  
Inert Material ◽  
Powder Formulation ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic

Abstract A gas-liquid chromatographic method for the determination of simazine in a wettable powder formulation containing about 80% active ingredient was collaboratively studied, using a matched pair scheme. The samples were dissolved in dimethylformamide containing dioctyl phthalate as an internal standard, chromatographed on Carbowax 20M, and detected by using a flame ionization detector. Analysis of the 2 samples, based on peak height measurements, showed the following results: 1.5% overall coefficient of variation, 1.03% coefficient of variation for random error, and 0.23% systematic error. Sample A was an 80% powder formulation; Sample B was a 5% dilution of Sample A by the addition of inert material. The coefficients of variation were 1.20% for Sample A and 1.54% for Sample B. The larger variation in Sample B most likely resulted from nonuniform mixing during the dilution of Sample A. Since all collaborators used the same reference standard, the variation found in Sample A is more indicative of the variability of the method. The method has been adopted as official first action.

Improved ultraviolet spectrophotometric method for determination of nitrate in natural waters

2002 ◽  
Vol 2 (2) ◽  
pp. 213-221 ◽  
Author(s):  
N. Kishimoto ◽  
I. Somiya ◽  
R. Taniyama
Keyword(s):  
Water Quality ◽  
Spectrophotometric Method ◽  
Standard Error ◽  
Coefficient Of Variation ◽  
Natural Waters ◽  
Uv Light ◽  
Rapid Determination ◽  
The Other ◽  
Extreme Conditions

An improved UV spectrophotometric method for determination of nitrate in natural waters was proposed and the determination accuracy of the method was discussed in this study. As a result of estimation of the proposed method, adoption of 215 and 220 nm for detection of nitrate and interfering substances resulted in decreasing standard error to about a half of that of a conventional spectrophotometric method. One of the reasons was thought that the coefficient of variation of relative absorbance of interfering substances (rs) at 215 nm was smaller and more stable than that at 275 nm, which was used in the conventional method. The other reason inferred was that most of the interfering substances absorbed UV light at wavelengths of 215 and 220 nm. Although rs has to be renewed when targeted water quality is under extreme conditions, the procedure of the proposed method is very simple, namely only measuring two UV absorbances of a filtrated sample, and more accurate than the conventional spectrophotometric method. Consequently, the proposed method is available for rapid determination of nitrate in natural waters.

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