Determination of Internal Insect Infestation of Wheat: Collaborative Study

1981 ◽  
Vol 64 (6) ◽  
pp. 1408-1410
Author(s):  
Richard L Trauba
Keyword(s):  
Collaborative Study ◽  
Tween 80 ◽  
Official Method ◽  
Insect Infestation ◽  
Improved Method ◽  
Adult Insect ◽  
Light Mineral ◽  
Wheat Kernels ◽  
Hydrolysis Of

Abstract An improved method has been developed for determining internal insect infestation of wheat kernels. The method involves acid hydrolysis of cracked wheat, wet sieving to remove the acid, transferring to a 2 L Wildman trap flask, deaeration by boiling, and treatment with Tween 80-Na4EDTA. Insects are extracted with light mineral oil. Reports from 6 collaborators showed that recovery was 95.92% for adult insect heads and 97.22% for larvae by the proposed method as compared with 87.05% and 6.12%, respectively, by the official method. The method has been adopted official first action.

Determination of Internal Insect Infestation of Oats: Collaborative Study

1985 ◽  
Vol 68 (4) ◽  
pp. 699-700
Author(s):  
Richard L Trauba
Keyword(s):  
Collaborative Study ◽  
Tween 80 ◽  
Mineral Oil ◽  
Insect Infestation ◽  
Improved Method ◽  
Adult Insect ◽  
Light Mineral ◽  
Hydrolysis Of ◽  
Wet Sieving

Abstract An improved method has been developed for determining internal insect infestation of oat kennels. The method involves alcohol defatting and acid hydrolysis of the cracked oats, wet sieving to remove the acid, transfer to a 2 L Wildman trap flask, deaeration by boiling, and treatment with Tween 80-Na.tEDTA. Insects are extracted with light mineral oil. Reports from 6 collaborators showed that recoveries averaged 88.98% for adult insect heads and 97.22% for larvae. The method has been adopted official first action.

Extraction of Light Filth from Whole Wheat Flour, Flotation Method: Collaborative Study

1994 ◽  
Vol 77 (5) ◽  
pp. 1150-1152
Author(s):  
Larry E Glaze ◽  
John R Bryce
Keyword(s):  
Wheat Flour ◽  
Tap Water ◽  
Collaborative Study ◽  
Tween 80 ◽  
Official Method ◽  
Test Portion ◽  
Whole Wheat Flour ◽  
Whole Wheat ◽  
Flotation Method

Abstract An additional extraction/flotation method for the determination of light filth in whole wheat flour was validated through a collaborative study. A 50 g test portion is boiled in a 3% HCI solution. The mixture is washed with hot tap water on a No. 230 sieve. Then the residue is boiled in iso-propanol, transferred to a No. 230 sieve, and washed again. The residue is transferred to a Wildman trap flask using 40% isopropanol. The filth is isolated by flotation in mineral oil and a mixture of Tween 80 and Na4EDTA in 40% isopropanol. Average recoveries by 8 collaborators were 88.8 and 91.7% for insect fragments and rat hairs, respectively. The extraction/flotation method for determination of light filth in whole wheat flour has been adopted first action by AOAC INTERNATIONAL as an additional procedure to the AOAC Official Method 941.16, Filth in Grain Products.

Extraction of Light Filth from Ground Allspice: Collaborative Study

1980 ◽  
Vol 63 (6) ◽  
pp. 1266-1268
Author(s):  
Russell G Dent ◽  
◽  
J G Eye ◽  
C C Freeman ◽  
E Hall ◽  
...  
Keyword(s):  
Hydrochloric Acid ◽  
Collaborative Study ◽  
Tween 80 ◽  
Mineral Oil ◽  
Improved Method ◽  
Aoac Method ◽  
Light Mineral ◽  
Wet Sieving

Abstract The present official AOAC method (44.120(a)(b), 13th Ed.) for extracting light filth from ground allspice uses flammable solvents and gives poor filth recoveries. An improved method has been developed which uses a single pretreatment with 40% isopropanol and hydrochloric acid, followed by wet sieving. After deaeration by boiling, the light filth is extracted from 40% isopropanol-Tween 80-tetrasodium EDTA with light mineral oil. Reports from all 6 collaborators showed that the proposed method resulted in 90 and 89% average recoveries of rodent hairs and insect fragments, respectively. The proposed method is recommended for adoption as official first action to replace AOAC (44.120(a)(b)) for allspice.

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.

scholarly journals Comparison of Babcock and Ether Extraction Methods for Determination of Fat Content of Cream: Collaborative Study

1996 ◽  
Vol 79 (4) ◽  
pp. 907-916 ◽  
Author(s):  
Joanna M Lynch ◽  
David M Barbano ◽  
J Richard Fleming
Keyword(s):  
Extraction Method ◽  
Collaborative Study ◽  
Extraction Methods ◽  
Fat Content ◽  
Official Method ◽  
Ether Extraction ◽  
Aoac Official ◽  
The Difference ◽  
Aoac Official Method

Abstract A modified Mojonnier ether extraction method for determination of the fat content of cream was developed based on the method for milk (AOAC Official Method 989.05). The cream Babcock method (AOAC Official Method 920.111 B-C) was modified to harmonize with the milk Babcock method (AOAC Official Method 989.04) and to clarify procedural details. Using the AOAC collaborative study format, 10 laboratories tested 9 pairs of blind duplicate heat-treated cream samples with a fat range of 30-45% using both methods. The statistical performance (invalid and outlier data removed) was as follows: mean % fat = 37.932, sr = 0.125, sR = 0.151, RSDr = 0.330, RSDR = 0.398, r = 0.354, and R = 0.427 for the ether extraction method. For the Babcock method, mean % fat = 38.209, sr = 0.209, SR = 0.272, RSDr = 0.548, RSDR = 0.712, r = 0.592, and R = 0.769. Average test results for fat from the Babcock method were 0.277% (absolute fat) greater than for the Mojonnier ether extraction method. The difference between methods, as a percentage of the average fat content of the samples, was 0.73%. This agrees with differences observed between the 2 methods for milk when 10 to 17 laboratories tested 7 milk samples in blind duplicate at bimonthly intervals over a 4-year period (average difference 0.029% fat, 0.78% as a percentage of average fat content). The Mojonnier ether extraction and Babcock methods for fat in cream have been adopted by AOAC INTERNATIONAL. The new Babcock method replaced the AOAC Official Method 920.111 B-C.

Determination of Maleic Hydrazide Residues in Tobacco and Vegetables

1973 ◽  
Vol 56 (5) ◽  
pp. 1164-1172
Author(s):  
Milan Ihnat ◽  
Robert J Westerby ◽  
Israel Hoffman
Keyword(s):  
Standard Deviation ◽  
Present Method ◽  
Maleic Hydrazide ◽  
Collaborative Study ◽  
Official Method ◽  
Sample Weight ◽  
Relative Standard ◽  
The Mean ◽  
Pipe Tobacco

Abstract The distillation-spectrophotometric method of Hoffman for determining maleic hydrazide has been modified to include a double distillation and was applied to the determination of 1–30 ppm maleic hydrazide residues in tobacco and vegetables. Recoveries of 1–23 μg added maleic hydrazide were independent of weight of maleic hydrazide, but did depend on sample and sample weight. The following recoveries were obtained from 0.5 g sample: pipe tobacco, 84%; commercially dehydrated potato, 83%; cigar tobacco, 81%; dried potato, 76%; fluecured tobacco, 73%; dried carrot, 71%. In the absence of sample, the recovery was 82%. When appropriate standard curves were used, maleic hydrazide levels determined in tobacco samples were essentially independent of sample weight in the range 0.1–3 g. The mean relative standard deviation for a variety of field-treated and fortified tobacco samples containing 1–28 ppm maleic hydrazide was 3%. The precision and sensitivity of this procedure seem to be substantial improvements over official method 29.111–29.117. It is recommended that the present method be subjected to a collaborative study.

Determination of VC-13 Nemacide Residues on Crops

1964 ◽  
Vol 47 (2) ◽  
pp. 287-288
Author(s):  
John I Teasley
Keyword(s):  
Alkaline Hydrolysis ◽  
Collaborative Study ◽  
Potassium Ferricyanide ◽  
Hydrolysis Of

Abstract A collaborative study was made of a method for the determination of VC-13 Nemacide residues, based on the alkaline hydrolysis of the pesticide to produce 2,4-dichlorophenol, which is measured colorimetrically with 4-aminoantipyrine and potassium ferricyanide. Results indicate that cleanup technique is critical and not effective for some crops. Several changes in the method were recommended for the next study. Three of five collaborators obtained satisfactory recoveries at levels of 50—250 ppb.

scholarly journals Improved method for determination of waxes in olive oils: reduction of silica and use of a less hazardous solvent

OCL ◽  
2020 ◽  
Vol 27 ◽  
pp. 20
Author(s):  
Andrea Milani ◽  
Paolo Lucci ◽  
Martina Sedran ◽  
Erica Moret ◽  
Sabrina Moret ◽  
...  
Keyword(s):  
Silicic Acid ◽  
Solid Phase ◽  
Internal Standard ◽  
Solvent Mixture ◽  
Official Method ◽  
Improved Method ◽  
Capillary Gc ◽  
Olive Oils ◽  
Solid Phase Extraction Cartridge

The evaluation of the content of waxes is request both by IOC Trade Standard and by Regulation (EEC) 2568/91 and its further amendments. The official method uses 15 g of silicic acid and elutes several fractions by using huge volumes of dangerous solvent (n-hexane). The developed method uses 1 g of silicic acid with a different particle size and less than 20 mL of solvent mixture, substituting n-hexane with less toxic isooctane. Briefly, after spiking with a suitable internal standard, oil sample is fractionated by SPE (Solid Phase Extraction) cartridge with 1 g of silica, waxes are eluted with 14 mL of isooctane/ethyl ether 99/1 (6 mL discarded and 8 mL collected), then, after elution sample is reconstitute in 200 μL of n-heptane and analysed by capillary GC. Data of “In home” validation, (repeatability, accuracy and recovery) and relative chromatograms are reported in this paper.

Extraction of Thrips and Other Whole or Equivalent Insects from Frozen Blackberries and Raspberries: Collaborative Study

1981 ◽  
Vol 64 (1) ◽  
pp. 194-195
Author(s):  
Russell G Dent ◽  
◽  
J Boese ◽  
M P Chaput ◽  
D Floyd ◽  
...  
Keyword(s):  
Coefficient Of Variation ◽  
Collaborative Study ◽  
Tween 80 ◽  
Mineral Oil ◽  
Light Mineral

Abstract A method was developed for the extraction of thrips and other whole or equivalent insects from frozen blackberries and raspberries. The method consisted of a thawing and drained weight step, followed by acid maceration. Berries were wet-sieved over a No. 25 sieve nested in a No. 80 sieve. The berry tissue retained on the No. 80 sieve was dehydrated with isopropanol and then treated with chloroform. The chloroform was stripped from the residue with isopropanol. The berry residue was extracted with light mineral oil from a 40% isopropanol-Tween 80- Na4EDTA mixture. The collaborative study was successfully completed with 83.3% average recoveries of thrips and a 19.2% coefficient of variation. The method has been adopted official first action.

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.

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