Collaborative Study of Improvements in the Distillation Procedure of the Official Method for Formaldehyde in Maple Sirup

1973 ◽  
Vol 56 (1) ◽  
pp. 132-134
Author(s):  
Calixte Hébert
Keyword(s):  
Collaborative Study ◽  
Official Method ◽  
Distillation Method ◽  
Modified Method ◽  
Quantitative Extraction ◽  
Coefficients Of Variation ◽  
Excellent Control ◽  
Final Operation

Abstract A collaborative study was conducted to show that in the quantitative extraction of formaldehyde from maple sirup by the official final action controlled distillation method, 31.184—31.189, accuracy is increased by the use of a thermostatically controlled flask heater, together with the proper insulation of the glass apparatus with asbestos cord. This eliminates undue condensation of the distillate and variations in the final and total distillation times. The modified method was tested by 9 laboratories and, from their individual results, the coefficients of variation for the total time of distillation proved that the method gave excellent control of the final operation. The changes have been adopted as official first action.

Collaborative Study of a Rapid Method for Determining Aflatoxins in Cottonseed Products

1975 ◽  
Vol 58 (4) ◽  
pp. 746-753
Author(s):  
Walter A Pons
Keyword(s):  
Systematic Error ◽  
False Positive ◽  
Collaborative Study ◽  
Statistical Treatment ◽  
Official Method ◽  
Modified Method ◽  
Collaborative Studies ◽  
Coefficients Of Variation ◽  
Aoac Method ◽  
The Mean

Abstract Eleven laboratories collaboratively studied a modification of the official final action AOAC method, 26.048–26.056, for determining aflatoxins in cottonseed products. An aflatoxinnegative meal, 6 contaminated meals, 4 contaminated meats (kernels) samples, and 2 ammonia-inactivated meals were used. Mean a (latoxin values, μg/kg, ranged from 6 to 223 (B1), 2 to 44 (B2), and 7 to 266 (total: B1 + B2). Only one laboratory reported a false-positive for the negative meal. The mean coefficients of variation for B1, B2, and total were 28, 56, and 29%, respectively, for meals; 35, 54, and 37%, respectively, for meats; and 35, 58, and 38%, respectively, for ammoniated meals. Statistical treatment of data from triplicate sets of meals and meats showed evidence for systematic error between laboratories. Since the modified method is considerably faster than the official method and yields precision estimates consistent with previous AOAC collaborative studies on determining aflatoxins, the method has been adopted as official first action.

Modified Extraction Procedure for Ipronidazole in Feeds Containing Bentonite

1974 ◽  
Vol 57 (1) ◽  
pp. 29-31
Author(s):  
Modest Osadca ◽  
Mercedes Araujo ◽  
Elmer De Ritter
Keyword(s):  
Collaborative Study ◽  
Extraction Procedure ◽  
Gas Liquid Chromatography ◽  
Buffer Gas ◽  
Modified Method ◽  
Quantitative Extraction ◽  
Collaborative Test ◽  
Coefficients Of Variation ◽  
Aoac Method ◽  
Benzene Extract

Abstract The extraction procedure in the AOAC method for ipronidazole in feeds, 38.A01— 38.A07, has been modified to eliminate the interference of bentonite with recovery of ipronidazole from mash feed and pellets. Quantitative extraction from mash feed or ground pellets is achieved by shaking the sample with benzene after a brief soaking with warm, aqueous pH 8 buffer. Gas-liquid chromatography is used to measure ipronidazole in the benzene extract as in the AOAC method. A preliminary collaborative test of the modified method by 3 laboratories on 8 samples of feed containing 0, 2, or 5% bentonite yielded average assays of 0.0061, 0.0058, and 0.0062% ipronidazole, with coefficients of variation averaging 2.4, 6.2, and 4.4%, respectively. Further collaborative study of the modified method is recommended.

Total Nitrogen in Fertilizer: Collaborative Study

1978 ◽  
Vol 61 (2) ◽  
pp. 299-306
Author(s):  
Paul R Rexroad ◽  
Gary F Krause
Keyword(s):  
Total Nitrogen ◽  
Collaborative Study ◽  
Oxidation Catalyst ◽  
Official Method ◽  
Probability Level ◽  
Sulfate Sulfur ◽  
Powder Method ◽  
Modified Method ◽  
Accuracy And Precision ◽  
Cent Nitrogen

Abstract A modified comprehensive nitrogen method, using 0.4 g C11SO4 as catalyst, is presented. This method plus a modified Raney powder method (mercury-free) with no metallic oxidation catalyst are compared with the AOAC comprehensive nitrogen method. Results from 19 collaborating laboratories for 11 samples are evaluated. The modified Raney method gave significantly low results on 2 samples: 21-7-14 (nitric phosphates-non-sulfate sulfur) and tryptophan. The results for the average per cent nitrogen for 11 samples from the modified comprehensive nitrogen method were comparable to those from the official method at the 95 % probability level; the overall pooled standard deviations were also similar. In this collaborative study, the modified method (with copper) was equal in accuracy and precision to the official method (with mercury). The modified comprehensive nitrogen method has been adopted as official first action.

scholarly journals Fine Tuning a Bile-Enzymatic-Gravimetric Total Dietary Fiber Method

1997 ◽  
Vol 80 (1) ◽  
pp. 89-94 ◽  
Author(s):  
Kenneth J Cranker ◽  
Katherine M Phillips ◽  
Maria Carmen Rita V Gonzales ◽  
Kent K Stewart
Keyword(s):  
Standard Deviation ◽  
Dietary Fiber ◽  
Collaborative Study ◽  
Original Method ◽  
Fine Tuning ◽  
Official Method ◽  
Total Dietary Fiber ◽  
Modified Method ◽  
Relative Standard ◽  
Wet Weight

Abstract A recently proposed bile-enzymatic-gravimetric total dietary fiber (TDF) method was modified and the new procedure was compared with the original method, the traditional AOAC enzymatic-gravimetric determination (AOAC Official Method 985.29), and another simplified AOAC procedure by analyzing several diet composites, including National Institute of Standards and Technology 1548 total diet reference material. The original and modified bile-enzymatic-gravimetric procedures also were compared by analyzing 9 food samples from a collaborative study of the original method. The modified method consistently yielded values about 10% lower than the original method but closer to reference values and to values from AOAC Offical Method 985.29, suggesting results that are more in line with accepted TDF standard methodology. Our modified method was used to analyze 180 fresh-frozen diet composites with TDF values ranging from 0.6 to 3.2 g/100 g wet weight. Samples were from 2 multicenter feeding studies sponsored by the National Heart, Lung and Blood Institute: DELTA (Dietary Effects on Lipoproteins and Thrombogenic Activity) and DASH (Dietary Approaches to Stop Hypertension). The mean relative standard deviation (RSD) for duplicate analyses was 1.1%. For 40 assays of a quality control diet composite over 9 months, the standard deviation was 0.1 g/100 g wet weight (4.9% RSD), indicating the method’s excellent precision for routine use.

scholarly journals Determination of Sulfamethazine in Swine and Cattle Feed by Reversed-Phase Liquid Chromatography with Post-Column Derivatization: Pre-Collaborative Study

2000 ◽  
Vol 83 (2) ◽  
pp. 255-259 ◽  
Author(s):  
Kendrick Albert ◽  
Robert L Smallidge
Keyword(s):  
Collaborative Study ◽  
Extraction Procedure ◽  
Internal Standard ◽  
Reversed Phase ◽  
Feed Additives ◽  
Official Method ◽  
Cattle Feed ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic

Abstract In-house validation of a liquid chromatographic method for determination of sulfamethazine in swine and cattle feed was performed to verify that the method was ready for collaborative study under AOAC INTERNATIONAL guidelines. In this method, sulfamerazine is added during the extraction procedure and is used as an internal standard to correct for variable recovery of sulfamethazine from a variety of swine and cattle feed matrixes. The determinative step involves the use of post-column derivatization with dimethylaminobenzaldehyde which reacts with the primary amine group on the sulfonamides. Detection is at 450 nm, a wavelength at which most co-extracted matrix materials and other feed additives do not absorb light. The results indicate that the method recovery, precision, and ruggedness meet normal criteria to be ready for a collaborative study. Fortification experiments over a range of sulfamethazine concentrations from 0.006 to 0.26% showed an overall recovery relative to the internal standard of 100 ± 2%. These studies include both swine and cattle feed matrixes. The mean recovery in the analysis of 3 beef cattle experimental feeds was 98.9%. The method results agreed with the AOAC INTERNATIONAL Official Method for colorimetric analysis of swine feed. Method precision was excellent during in-house validation studies, with coefficients of variation (CVs) ranging from about 0.5 to 3%. The method ruggedness was verified with an overall CV of 3.5%.

Determination of Amprolium in Feeds: Collaborative Study

1979 ◽  
Vol 62 (3) ◽  
pp. 621-623
Author(s):  
E Jack Davis
Keyword(s):  
Aluminum Oxide ◽  
Collaborative Study ◽  
Official Method ◽  
Modified Method

Abstract The official final action method, 42.028-42.032, for determining amprolium in feeds was modified by a change in the preparation of aluminum oxide for chromatography. A premix containing 0.5% amprolium was collaboratively studied by the modified and the official methods. Compared with the modified method, 87.7% of the drug was recovered from the premix by using the official method. The modification makes possible the assay of premixes as well as finished feeds. The official final action method has been modified to incorporate this change.

Analysis of Ergotamine Tartrate Suppository Preparations

1963 ◽  
Vol 46 (4) ◽  
pp. 634-636
Author(s):  
Thomas G Alexander
Keyword(s):  
Collaborative Study ◽  
Official Method ◽  
Modified Method ◽  
Ergotamine Tartrate

Abstract The official method for the analysis of ergotamine tartrate tablets has been adapted to the analysis of ergotamine tartrate suppository preparations. A collaborative study was conducted on this modified method. The method is recommended for adoption as official, first action.

Collaborative Study of a Microbiological Method for the Assay of Neomycin Sulfate in Feeds

1973 ◽  
Vol 56 (5) ◽  
pp. 1154-1160
Author(s):  
Billy Joe Williams
Keyword(s):  
Coefficient Of Variation ◽  
Reliable Method ◽  
Collaborative Study ◽  
Inhibition Zone ◽  
Official Method ◽  
Microbiological Method ◽  
Average Recovery ◽  
Modified Method ◽  
Neomycin B ◽  
Neomycin Sulfate

Abstract The official method for the microbiological assay of neomycin sulfate in feeds was modified by adding pH 8.0 Tris buffer to and deleting CaC12 from the base and seed agars. The modified method was collaboratively studied by 13 laboratories. Each laboratory performed single assays of 4 feed types at 4 medication levels over 4 months. The average recovery for all collaborators was 115.6% of theory with a coefficient of variation of 20.4%. Neither order of assay, feed type, nor ratio of neomycin B to C in the premix significantly affected the assays. Inhibition zone diameters were significantly larger for standard solutions prepared in 1 + 24 dilutions of inactivated feed extracts than for identical concentrations of standard in 1+49 dilutions of identical feed extracts. This study has been discontinued and a search for a more reliable method has been initiated.

Mineral Oil Vacuum Distillation Method for Nitrosamines in Fried Bacon, with Thermal Energy Analyzer: Collaborative Study

1982 ◽  
Vol 65 (6) ◽  
pp. 1319-1332
Author(s):  
Earl L Greenfield ◽  
Wertice J Smith ◽  
Anthony J Malanoski ◽  
◽  
M Benson ◽  
...  
Keyword(s):  
Thermal Energy ◽  
Vacuum Distillation ◽  
Collaborative Study ◽  
Mineral Oil ◽  
Distillation Method ◽  
Energy Analyzer ◽  
Coefficients Of Variation

Abstract Nine laboratories participated in a collaborative study of a method for determining 6 nitrosamines, dimethylnitrosamine, diethylnitrosamine, dibutylnitrosamine, nitrosopiperidine, nitrosopyrrolidine, and nitrosomorpholine, in the 5-17 ppb range. The coefficients of variation for repeatability were 10.8, 8.5,10.4, 8.5, 8.7, and 7.8% with corresponding coefficients of variation for reproducibility of 16.4, 12.0,13.6,10.8,11.2, and 10.3% and recoveries of 89.6, 91.6, 84.7, 90.0, 89.6, and 88.1%, respectively. The method was adopted official first action.

Microbiological Assay of Streptomycin in Feeds: 1971 Collaborative Study

1972 ◽  
Vol 55 (4) ◽  
pp. 714-717
Author(s):  
John J Mayernik ◽  
Gloria Y Fiori ◽  
Shirley Hughes
Keyword(s):  
Sample Size ◽  
Reference Point ◽  
Collaborative Study ◽  
Microbiological Assay ◽  
Modified Method ◽  
Coefficients Of Variation ◽  
Aoac Official ◽  
Low Levels

Abstract The AOAC official first action method for the determination of streptomycin in feed in which the regular streptomycin assay agar is used was modified for application to the assay of low levels of streptomycin. The modifications consist of (1) increasing the sample size, (2) reducing the amount of agar in the assay plates, (3) lowering the concentration of the reference point on the assay plates, and (4) incubating the plates at 22–25°C instead of 37°C. Fifteen collaborators used the modified method to assay 6 feeds containing 5–30 g streptomycin/ ton. Mean recoveries ranged from 91.7 to 111.0% and coefficients of variation ranged from 5.8 to 8.7%. The method modified as described has been adopted as official first action for the assay of feeds containing 5–30 g streptomycin/ton.

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