Chloroform-Methanol Extraction Method for Determination of Fat in Foods: Collaborative Study

1983 ◽  
Vol 66 (4) ◽  
pp. 927-932 ◽  
Author(s):  
Chester E Daugherty ◽  
Harry G Lento ◽  
◽  
M L Adams ◽  
E W Beckert ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Extraction Method ◽  
Collaborative Study ◽  
Fat Content ◽  
Processed Foods ◽  
Methanol Extraction ◽  
Complete Extraction ◽  
Standard Deviations ◽  
Chloroform Methanol

Abstract Achloroform-methanol extraction method (complete extraction of fat in 3 min) for determining fat in processed and prepared foods has been studied collaboratively. Fourteen collaborators reported single replicate fat results on 7 samples representative of various food types and 2 spiked samples by the proposed method. Each sample was accompanied by a blind duplicate. For statistical purposes, the blind duplicates were treated as paired observations, and there were 2 laboratory outliers. There was a 97.9% agreement among the results from the remaining 12 collaborators and the Associate Referee for the unfortified samples. Recoveries of 93.8 and 98.3% were obtained on fortified samples, based on results obtained from 11 collaborators. The statistical analysis of the results indicate (ranges for standard deviations were Sr = 0.083-0.528, Sb = 0.101-0.379, Sd = 8.130-0.631, for fat values ranging from 1.58 to 26.91%) that this method is adequate for quantitating the fat content in a wide variety of processed foods for nutritional labeling. The method has been adopted official first action.

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.

Gas Chromatographic-Chemiluminescence Method for Determination of Volatile NNitrosamines in Minced Fish-Meat and Surimi-Meat Frankfurters: Collaborative Study

1990 ◽  
Vol 73 (6) ◽  
pp. 947-952
Author(s):  
John W Pensabene ◽  
Walter Fiddler ◽  
John G Phillips
Keyword(s):  
Extraction Method ◽  
Solid Phase ◽  
Collaborative Study ◽  
Energy Analyzer ◽  
Chemiluminescence Method ◽  
Fish Meat ◽  
Relative Standard ◽  
Minced Fish ◽  
Standard Deviations

Abstract A collaborative study was carried out on a solid-phase extraction method for separating volatile N-nltrosamlnes, particularly N-nltrosodlmethylamlne (NDMA), from combination minced fish or surlml-meat frankfurters with detection by gas chromatography-chemllumlnescence (thermal energy analyzer). The results from the 10 collaborators were evaluated using the most recent AOAC guidelines for determining outliers and for the analysis of variance. For NDMA, repeatability standard deviations, sr, ranged from 0.56 to 2.25; repeatability relative standard deviations, RSDr, ranged from 8.9 to 11.5%. Reproducibility standard deviations, sR, for NDMA ranged from 1.40 to 6.49, and reproducibility relative standard deviations, RSDR, ranged from 24.2 to 28.9%. Our data compared favorably to the reproducibility (RSDR) curve of Horwltz. The method has been adopted official first action by AOAC.

Determination of Lipids in Fish Meal

1966 ◽  
Vol 49 (5) ◽  
pp. 946-949 ◽  
Author(s):  
C F Lee ◽  
M E Ambrose ◽  
P Smith
Keyword(s):  
Ethyl Ether ◽  
Alkaline Hydrolysis ◽  
Extraction Method ◽  
Fish Meal ◽  
Total Lipids ◽  
Methanol Extraction ◽  
Aoac Method ◽  
Chloroform Methanol

Abstract Lipids were extracted from a series of twelve menhaden meals by six methods, and results were compared. The chloroformmethanol extraction method developed by Smith, et al., extracts approximately the same amount of lipids as the official AOAC method, 22.037. The Torry-TNO method with chloroform-methanol extraction, and acid and alkaline hydrolysis methods extract lesser amounts of lipids, but all methods extract more than the ethyl ether method, 22.032. The Smith-Ambrose-Knobl method, rather than AOAC method 22.037, is recommended for extraction of total lipids from fish meal because of its simplicity and efficiency.

Comparison of Babcock and Ether Extraction Methods for Determination of Fat Content of Milk: Collaborative Study

1988 ◽  
Vol 71 (5) ◽  
pp. 898-914 ◽  
Author(s):  
David M Barbano ◽  
Jenny L Clark ◽  
Chapman E Dunham
Keyword(s):  
Extraction Method ◽  
Collaborative Study ◽  
Raw Milk ◽  
Extraction Methods ◽  
Fat Content ◽  
Absolute Level ◽  
Ether Extraction ◽  
Relative Standard ◽  
Standard Deviations ◽  
The Difference

Abstract Eleven collaborating laboratories analyzed 18 blind duplicate pairs of raw milk samples for fat by the Babcock method and by a modified Mojonnier ether extraction method in 7 round robins conducted over a 14 month period. Ten laboratories used the Babcock method and 10 used the modified Mojonnier method. Fat content of samples ranged from approximately 2.7 to 5.6%. Mean test value of samples analyzed was approximately 3.9% fat. Average standard deviations of within-laboratory repeatability (Sr) of the Babcock and ether extraction methods were 0.029 and 0.015% fat, respectively. Average standard deviations of between-laboratory reproducibility (SR) of the Babcock and ether extraction methods were 0.039 and 0.020% fat, respectively. Average repeatability relative standard deviations (RSDr) for the Babcock and ether extraction methods were 0.742 and 0.396%; average reproducibility relative standard deviations (RSDR) were 1.014 and 0.512%, respectively. Mean repeatability values (r) and reproducibility values (R) were 0.081 and 0.111% for Babcock and 0.044 and 0.056% for ether extraction, respectively. The ether extraction method demonstrated consistently better within- and between-laboratory agreement. The overall mean test value for the Babcock method was significantly higher (0.021% fat) than that for ether extraction. The difference between Babcock and ether extraction fat test results was different for different farms. In addition, the mean difference between percent fat determined by the Babcock and ether extraction methods was different in different months. There was no correlation in the difference between Babcock and ether extraction methods with the absolute level of fat in the samples in the range of 2.7 to 5.6% fat. The modifications of the AOAC Babcock method and the modified Mojonnier ether extraction method have been approved interim official first action.

Manual Determination of Minced Fish Flesh in Mixed Fillet-Minced Cod Blocks: Collaborative Study

1988 ◽  
Vol 71 (1) ◽  
pp. 38-40
Author(s):  
J Perry Lane ◽  
Robert J Learson ◽  
◽  
S Berube ◽  
N Farstad ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Rapid Method ◽  
Collaborative Study ◽  
Fish Flesh ◽  
Coefficients Of Variation ◽  
Minced Fish ◽  
Standard Deviations

Abstract A simple, rapid method for determining the amount of minced fish in mixed fillet-minced cod blocks was tested by 9 collaborators. Each collaborator first examined 2 practice blocks containing 20% mince, and then examined 6 blind duplicate samples of 5 lb cod blocks from each of 3 test lots containing, respectively, 26.25, 18.75, and 12.5% mince. The data from one of the 9 collaborators was not usable because of a malfunctioning scale. Standard deviations (SD) for the 3 lots (all 8 collaborators combined) were 1.77, 1.51, and 1.65, and coefficients of variation (CV) were 6.8, 8.9, and 16.2%, respectively. For comparison, the results of an informal collaborative study by 10 participants on 16.5 lb mixed cod blocks containing 20.1% mince were SD 2.72 and CV 0.136%. Collaborators reported no problems with the method, and statistical analysis shows the method to be sufficiently precise for this type of determination. The method has been adopted official first action for cod.

Collaborative Study of the Spectrophotometric Determination of Procainamide Hydrochloride

1976 ◽  
Vol 59 (4) ◽  
pp. 807-810
Author(s):  
Jeffrey C Hamm
Keyword(s):  
Sodium Hydroxide ◽  
Acid Medium ◽  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
Collaborative Study ◽  
Dosage Forms ◽  
Standard Deviations

Abstract The USP analysis for procainamide HCl is titrimetric and relatively nonspecific, capsule and tablet dyes may interfere, and the method is not applicable to coated tablets. In the spectrophotofluorometric method the sample deteriorates when exposed to a xenon source. In the ultraviolet spectrophotometric method reported here, the sample is dispersed in acid medium, possible interferences are extracted in chloroform, base is added, procainamide is extracted in chloroform, the residue is dissolved in sodium hydroxide, and the compound is measured by absorption at 272 nm and comparison with a standard. Recoveries of standards added to capsule, tablet, and injection composites ranged from 99.3 to 102%. Twelve collaborators reported duplicate assay results for all 3 dosage forms with per cent standard deviations for 5 samples ranging from 1.01 to 1.27%. The method has been adopted as official first action.

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