Collaborative Study of an Improved Method for the Isolation of Filth from Starches

1972 ◽  
Vol 55 (1) ◽  
pp. 62-63
Author(s):  
John S Gecan ◽  
Paris M Brickey
Keyword(s):  
Acid Hydrolysis ◽  
Collaborative Study ◽  
Official Method ◽  
Improved Method ◽  
Modified Method ◽  
Aoac Method ◽  
Wet Sieving

Abstract The official AOAC method for filth in starches, 40.056, has been modified to obtain better recovery of extraneous materials. In lieu of wet sieving on a No. 140 sieve, the modified method utilizes No. 230 wet sieving followed by an acid hydrolysis, if excessive starch material remains on the sieve. A limited collaborative study comparing the improved method with the official method resulted in higher recoveries of rodent hairs and equivalent recoveries of other spike elements by the improved method. The improved method is recommended for adoption as official first action to replace 40.056.

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.

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.

Collaborative Study of a Modified Method for the Extraction of Light Filth from Ground White Pepper, Cardamom, Celery Seed, Coriander, and Ginger

1977 ◽  
Vol 60 (1) ◽  
pp. 117-121
Author(s):  
Russell G Dent
Keyword(s):  
Collaborative Study ◽  
Mineral Oil ◽  
Improved Method ◽  
White Pepper ◽  
Modified Method ◽  
Celery Seed ◽  
Action Methods ◽  
Wet Sieving

Abstract An improved method has been developed for the extraction of light filth from 5 ground spices, ginger, white pepper, coriander, celery seed, and cardamom. The method, a modification of 44.120, utilizes a cold isopropanol defatting, followed by wet sieving and flotation of light filth from 40% isopropanol with HCl and mineral oil-heptane (85+15). Collaborative results show that the proposed method is more rapid to perform than the present official first action methods, 44.116 and 44.120, and yields better recoveries. The method has been adopted as official first action.

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.

Improved Method for Extraction of Filth from Cheese

1986 ◽  
Vol 69 (4) ◽  
pp. 712-713
Author(s):  
Mary-Ann Gardiner ◽  
Diane McClymont Peace
Keyword(s):  
Microscopic Examination ◽  
Lower Cost ◽  
Official Method ◽  
Improved Method ◽  
Soft Cheese ◽  
Aoac Method ◽  
Wet Sieving

Abstract An official AOAC method for detection of total filth in hard and soft cheese was modified to (a) achieve digestion of cheese at lower cost, (b) improve filtration rates, and (c) facilitate microscopic examination of the filth collected. The modifications involve a wet-sieving step, a reduction in the amounts of liquid filtered and pancreatin used, a detergent defatting step, and an acid boil step, if required. Average recoveries ranged from 85 to 100%. The method modifications should be collaboratively studied so changes in the official method can be recommended

Collaborative Study of Modified AOAC Method of Analysis for Nitrite in Meat and Meat Products

1977 ◽  
Vol 60 (3) ◽  
pp. 594-599 ◽  
Author(s):  
Rosemary Nicholas Fiddler
Keyword(s):  
Random Error ◽  
Collaborative Study ◽  
Meat Products ◽  
Matched Pair ◽  
Official Method ◽  
Griess Reagent ◽  
Standard Curve ◽  
Modified Method ◽  
Color Development ◽  
Aoac Method

Abstract A modified version of the AOAC method of analysis for nitrite in meat and meat products was tested collaboratively by 23 laboratories. Results were compared with those obtained by the official AOAC method. Recommended modifications include: (a) substitution of N-(1-naphthyl) ethylenediamine and sulfanilamide for Griess reagent, (b) separate addition and 1:10 dilution of the above reagents, (c) 20 min color development and absorbance read at 540 nm, (d) substitution of NaNO2 for AgNO2 and NaCl, (e) omission of mercuric chloride, (f) screening of filter paper for nitrite contamination, (g) more precise dilution of sample aliquot, and (h) standard curve linear up to 10 μg N/50 ml. Results were statistically treated by Youden’s technique for comparing 2 methods, using a matched pair sample scheme. The random error for the modified method was significantly lower than the random error for the official method. A t-test showed no difference in bias between the 2 methods.

Collaborative Study of Rapid Fat Determination in Meat and Meat Products by Modification of the AOAC Method

1973 ◽  
Vol 56 (5) ◽  
pp. 1140-1143 ◽  
Author(s):  
Julio D Pettinati ◽  
Clifton E Swift ◽  
Edward H Cohen
Keyword(s):  
Standard Deviation ◽  
Collaborative Study ◽  
Meat Product ◽  
Statistical Treatment ◽  
Meat Products ◽  
Complete Removal ◽  
Official Method ◽  
Pork Sausage ◽  
Modified Method ◽  
Aoac Method

Abstract The rapid method for fat determination reported by this laboratory has been evaluated by 10 collaborating laboratories in a comparison with the AOAC method. The method is similar to the official method except that a 3–4 g sample of meat or meat product is dried in an open extraction thimble for 30 min at 125°C and extracted with ethyl ether for 45 min at maximum reflux, and fat content is determined gravimetrically after complete removal of solvent from the extract. Collaborators performed 6 replicate analyses on samples of ground beef, frankfurters, and fresh pork sausage by both methods. A statistical treatment of the results showed that fat contents determined by the modified method agreed with those obtained by the official method. The expected standard deviation, se, averaged for the 3 types of meat product, was ±0.83% fat which is 1.5 times the value obtained by the official method, ±0.56% fat.

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.

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.

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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