Chromatographic Estimation of Vitamin A in Mixed Feeds

1945 ◽  
Vol 17 (11) ◽  
pp. 689-692 ◽  
Author(s):  
Maxwell L. Cooley ◽  
James B. Christiansen ◽  
Carl H. Schroeder
Keyword(s):  
1960 ◽  
Vol 43 (1) ◽  
pp. 25-28
Author(s):  
F Howard Tinkler ◽  
Joseph B Hanley ◽  
Robert W Lehman
Keyword(s):  

1974 ◽  
Vol 57 (4) ◽  
pp. 903-909
Author(s):  
Donald B Parrish

Abstract The official final action method for determining vitamin A in mixed feeds, 39.008–39.013, was simplified where possible, principally in extraction and transfer procedures and by omission of chromatography, and was modified to apply to a larger variety of feed and food products. Twenty-two analysts of various degrees of experience participated in the collaborative study of the method, using 6 products. After outliers were eliminated by the Dixon test, data were analyzed and averages were compared with amounts of vitamin A known to be, or estimated, in each sample. The average, per cent deviation from added amount, standard deviation, and coefficient of variation, respectively, on each sample were: breakfast cereal (Sample 1), 23.8 μg/g, 2% less, 3.08, 13% ; mixed feed (or premix), 12.6 μg/g, 5% less, 0.99, 8%; mixed feed containing carotenoid pigments (Sample 3 ), 4.5 μg/g, 3% more, 0.66, 15%; mixed feed without pigments, 4.5 μg/g, 3% more, 0.57, 13% ; liquid feed supplement, 11.4 μg/g, 9% less, 1.44, 12%; powdered breakfast drink, 19.6, 7% less, 1.91, 10%. Some analysts did not correct for pigments in Samples 1 and 3, or for losses on analysis, which could account in part for the degree of variation and for the lower values on some samples. The method has been adopted as official first action to replace 39.008-39.013.


1957 ◽  
Vol 40 (3) ◽  
pp. 865-876
Author(s):  
D B Parrish
Keyword(s):  

1959 ◽  
Vol 42 (3) ◽  
pp. 520-524
Author(s):  
D B Parrish
Keyword(s):  

1956 ◽  
Vol 39 (1) ◽  
pp. 126-139
Author(s):  
D B Parrish ◽  
H A Smith
Keyword(s):  

1953 ◽  
Vol 36 (3) ◽  
pp. 812-819
Author(s):  
Maxwell L Cooley
Keyword(s):  

1960 ◽  
Vol 43 (1) ◽  
pp. 30-34
Author(s):  
D B Parrish
Keyword(s):  

1949 ◽  
Vol 21 (5) ◽  
pp. 593-595 ◽  
Author(s):  
M. L. Cooley ◽  
J. B. Christiansen ◽  
R. C. Koehn
Keyword(s):  

1958 ◽  
Vol 41 (3) ◽  
pp. 593-599
Author(s):  
D B Parrish
Keyword(s):  

1954 ◽  
Vol 37 (3) ◽  
pp. 742-748
Author(s):  
Maxwell L Cooley
Keyword(s):  

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