Modification of AOAC Method for Determination of Soluble Solids in Tomato Products

1972 ◽  
Vol 55 (4) ◽  
pp. 809-810
Author(s):  
Frank C Lamb
Keyword(s):  
Sample Preparation ◽  
Excellent Agreement ◽  
Soluble Solids ◽  
Official Method ◽  
Aoac Method ◽  
Centrifugation Technique ◽  
Tomato Products ◽  
Good Agreement

Abstract The official first action method for soluble solids in tomato products, 32.008–32.010, was modified to permit the optional use of an ultracentrifuge to prepare samples for readings in a refractometer. Excellent agreement was obtained between the official method which specifies filtration and the centrifugation technique. Good agreement was also obtained between 2 laboratories using the centrifugation technique. The official method was modified to include the optional use of an ultracentrifuge for sample preparation.

Allyl Isothiocyanate in Mustard Seed

1970 ◽  
Vol 53 (1) ◽  
pp. 1-3 ◽  
Author(s):  
Donald L Andersen
Keyword(s):  
Allyl Isothiocyanate ◽  
Mustard Seed ◽  
Official Method ◽  
Average Recovery ◽  
Aoac Method ◽  
Aoac Official ◽  
Mustard Seeds ◽  
Column Preparation ◽  
Aoac Official Method

Abstract A new GLC method for the determination of allyl isothiocyanate in mustard seed was compared to a method of the Midwest Research Institute and to a combination of the AOAC official method and the proposed method. Twelve collaborators compared the AOAC method and the GLC method, using whole mustard seeds. Each collaborator assayed three seed portions by both methods. The range, standard deviation, and coefficient of variation are less for each seed portion by the proposed than by the official method. The average recovery value of allyl isothiocyanate in the prepared standard solutions is lower, using the proposed GLC procedure, but seed assay values are significantly and consistently higher for each seed portion when compared with the results for the AOAC method. Reports from the collaborators also indicate that the proposed method is rugged, as the GLC column preparation was subjected to many changes. It is recommended that the GLC method be adopted as official first action.

Collaborative Study of the Quantitative Gas-Liquid Chromatographic Determination of Fusel Oil and Other Components in Whisky

1972 ◽  
Vol 55 (3) ◽  
pp. 549-556
Author(s):  
J H Kahn ◽  
E T Blessinger
Keyword(s):  
Ethyl Acetate ◽  
Collaborative Study ◽  
Chromatographic Determination ◽  
Official Method ◽  
Fusel Oil ◽  
Fusel Alcohols ◽  
Aoac Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract Fifteen chemists participated in a collaborative study for the quantitative pas-liquid chromatographic determination of the individual fusel alcohols and ethyl acetate in whisky. Two levels of congeners represented by 4 coded samples of whisky were analyzed by using t h e proposed method, employing a glycerol-1,2,6-hexanetriol column, and the official AOAC method, 9.063-9.065. Since isobutyl and the atnyl alcohols comprise by far the greatest part of fusel oil, their determination is of major importance to the total fusel oil content . Statistical analyses show that the proposed method is superior to the AOAC method for the determination of these alcohols, whereas the official method is superior for the determination of ethyl acetate and n-propyl alcohol. In general, collaborators employing modern instrumentation preferred the proposed method over the AOAC method. The former method also separates and permits the quantitative measurement of active amyl and isoamyl alcohols. The proposed method has been adopted as official first action as an alternative to 9.063–9.065 for the determination of higher alcohols and ethyl acetate in whisky.

Collaborative Study of the Determination of Phosphorus in Gelatin, Dessert Preparations, and Mixes

1972 ◽  
Vol 55 (3) ◽  
pp. 581-582
Author(s):  
Roger G Burkepile
Keyword(s):  
Collaborative Study ◽  
Official Method ◽  
Standard Samples ◽  
Preliminary Work ◽  
Aoac Method ◽  
Standard Deviations

Abstract A collaborative study of the proposed method for phosphorus in gelatin, dessert preparations, and mixes has been conducted. The present AOAC method for phosphorus in fertilizers, 2.023–2.025(a), was modified for this study. Preliminary work by the Associate Referee involving 4 phosphorus standard samples compared the proposed method with the official final action AOAC method for gelatin, 23.004. Additionally, phosphorus standard spikes in gelatin at the 1 and 10 mg P2O5, levels were determined by the proposed method. The proposed method is faster and more sensitive than the official method and is as accurate. Five collaborators and the Associate Referee analyzed 4 prepared samples containing various levels of phosphorus by the proposed method. The standard deviations varied from 0.005 for a 225 Bloom gelatin containing an average of 0.273% P2O5 to 0.016 for a strawberry-flavored commercial gelatin with added lecithin containing an average of 0.110% P2O5. The proposed method has been adopted as official first action to replace 23.004, which was repealed, official first action.

Simultaneous Determination of Volatile Acids and Sulfur Dioxide in Alcoholic Beverages by Microdiffusion

1967 ◽  
Vol 50 (2) ◽  
pp. 307-311
Author(s):  
Joseph L Owades ◽  
Joseph M Dono
Keyword(s):  
Sulfur Dioxide ◽  
Simultaneous Determination ◽  
Excellent Agreement ◽  
Alcoholic Beverages ◽  
Small Samples ◽  
Volatile Acid ◽  
Diffusion Cell ◽  
Aoac Method ◽  
A New Technique

Abstract A new technique has been developed for determining both volatile acid and sulfur dioxide in beer, wines, and distilled liquors. The new method avoids the troublesome distillation common to other methods by use of microdiffusion in an especially modified diffusion cell. Small samples are reqviired and many replicates can be performed in one day. Results were in excellent agreement with the AOAC method for wine, and precision was very good

Determination of Geotrichum Mold in Comminuted Fruits and Vegetables: Collaborative Study

1982 ◽  
Vol 65 (5) ◽  
pp. 1095-1096
Author(s):  
Stanley M Cichowicz ◽  
Ruth Bandler ◽  
◽  
R Bandler ◽  
G Dzidowski ◽  
...  
Keyword(s):  
Crystal Violet ◽  
Fruits And Vegetables ◽  
Collaborative Study ◽  
Green Beans ◽  
Aoac Method ◽  
Tomato Products

Abstract The official AOAC method for determination of Geotrichum mold in canned fruits and vegetables (44.079) requires a series of 3 sieves, Nos. 8, 16, and 230, to separate the packing liquid from the product and the mold from the packing liquid. Although this method has been successful for whole or coarsely chopped products (e.g., green beans, potatoes, carrots, and beets), finely divided products such as fruit purees and tomato products tend to clog the sieves. A method was developed in which the product is centrifuged, diluted by volume, stained with crystal violet, and counted with the sieving steps eliminated. The proposed method was adopted official first action.

Extraction of Lipids from Raw Beef Lean by Using Various Solvent Systems

1967 ◽  
Vol 50 (2) ◽  
pp. 250-255 ◽  
Author(s):  
Susie N Hagan ◽  
Elizabeth W Murphy ◽  
Lydia M Shelley
Keyword(s):  
Sample Preparation ◽  
Drying Method ◽  
Preparation Methods ◽  
Drying Procedures ◽  
Aoac Method ◽  
Solvent Systems ◽  
Total Fat ◽  
Layer Chromatography ◽  
Chloroform Methanol

Abstract Study shows that chloroform-methanol extraction to remove lipids from beef yielded percentages of total fat equal to or greater than those obtained by the AOAC method. The ratio of phospholipid to triglyceride was always higher in the chloroform-methanol extracted samples. Six extraction methodsolvent system combinations, three drying procedures, and two sample preparation methods were compared. Tlie extracted lipids were separated by thin layer chromatography. The ratio of phospholipid to triglyceride was calculated after the spectrophotometric determination of the ester groups present. Acid-hydrolysis-Rohrig gave the lowest yield of total lipid and of phospholipid. Sample preparation method or drying method caused few significant dif. ferenccs in the proportions of total solids and of total lipids in the beef cuts analyzed

Comparison of Sample Preparation Methods for Phosphorus in Grains and Stock Feeds

1968 ◽  
Vol 51 (4) ◽  
pp. 771-773
Author(s):  
Aaron E Rash
Keyword(s):  
Sample Preparation ◽  
Perchloric Acid ◽  
Sodium Molybdate ◽  
The Other ◽  
Acid Digestion ◽  
Preparation Methods ◽  
Commercial Feeds ◽  
Sample Preparation Methods ◽  
Good Agreement

Abstract The nitric-perchloric acid digestion, 22.070(b) and 22.073, for the determination of phosphorus in grains and stock feeds was compared with three other methods of sample preparation (destruction of organic material) : quinoline molybdate precipitation, perchloric-sulfuric-sodium molybdate digestion, and the plant method. The values obtained by the nitric-perchloric acid method were not in good agreement with those obtained by the other methods studied. Six samples of commercial feeds and one barley sample were analyzed. The barley sample gave very poor recoveries by method 22.073.

Extraction of Light Filth from Tea: Collaborative Study

1981 ◽  
Vol 64 (2) ◽  
pp. 287-290
Author(s):  
Faith F Lim ◽  
◽  
J Barnett ◽  
A Bright ◽  
M P Chaput ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Collaborative Study ◽  
Tween 80 ◽  
Mineral Oil ◽  
Plant Residue ◽  
Official Method ◽  
Existing Problems ◽  
Aoac Method ◽  
Filter Papers ◽  
Wet Sieving

Abstract The present AOAC method for determining insect and rodent filth in tea is time-consuming because it produces filter papers which are heavy in plant residue and therefore requires long paper-reading times. Anew method for the analysis of light filth in tea was developed to remedy existing problems and to improve recoveries. The method consists of the following steps: sample preparation, wet sieving, dilution with 40% isopropanol, extraction with Tween 80-Na4EDTA-40% isopropanol, flotation with mineral oil-heptane, and trapping off in a Wildman trap flask. In an interlaboratory collaborative study, analysts reported combined insect fragment recoveries of 99.2% for the proposed method and 93.0% for the AOAC method; the same analysts recorded combined rodent hair recoveries of 92.2% for the proposed method and 47.6% for the official method. Average times for reading individual subsamples were 9 min for the proposed method and 27 min for the AOAC method. The proposed method has been adopted official first action.

Spectrophotometric Determination of Atropine Sulfate in the Presence of Phenylmercury (II) Acetate

1981 ◽  
Vol 64 (4) ◽  
pp. 855-859
Author(s):  
Abdel Aziz M Wahbi ◽  
Magda Barary
Keyword(s):  
Least Squares ◽  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
Atropine Sulfate ◽  
Official Method ◽  
Method Of Least Squares ◽  
Orthogonal Function ◽  
Two Component ◽  
Good Agreement

Abstract Two-component spectrophotometric method of analysis using 2 wavelengths, the method of least squares using absorbances, the method using 2-orthogonal function coefficients, and the method of least squares using orthogonal function coefficients have been applied to the determination of atropine sulfate in the presence of phenylmercury (II) acetate, compounds whose spectra overlap. The first method gave erroneous results; the second method gave satisfactory results for synthetic mixtures. The fourth method was superior, especially in the presence of irrelevant absorption. It has been successfully used for determining atropine sulfate in injection solutions in which a cubic irrelevant absorption was present. Results were in good agreement with those obtained by the official method.

Determination of Moisture in Raisins

1972 ◽  
Vol 55 (1) ◽  
pp. 202-208
Author(s):  
H R Bolin ◽  
A E Stafford ◽  
B E Mackey
Keyword(s):  
Method Section ◽  
Temperature Range ◽  
Dried Fruit ◽  
Aoac Method ◽  
Good Agreement

Abstract The official AOAC method, section 22.012, and the dried fruit moisture tester method for determining moisture in raisins have been collaboratively studied. There is good agreement between the 2 methods with less than ± 1% moisture difference being noted in the 10–20% range. Results indicate that the dried fruit moisture charts are accurate throughout their temperature range. It is recommended that the dried fruit moisture tester method be adopted as official first action for the determination of moisture in raisins.

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