Determination of Vitamin B12 in Dry Feeds by Atomic Absorption Spectrophotometry

1976 ◽  
Vol 59 (3) ◽  
pp. 580-581
Author(s):  
Larry L Whitlock ◽  
James R Melton ◽  
Toby J Billings
Keyword(s):  
Vitamin B12 ◽  
Atomic Absorption ◽  
Cobalt Oxide ◽  
Cobalt Content ◽  
Atomic Absorption Spectrophotometry ◽  
Absorption Spectrophotometry ◽  
Aoac Method

Abstract Vitamin B12 was determined in dry feeds by atomic absorption spectrophotometry (AAS). Samples containing B12 were extracted with an assay solution, 5 g EDTA was added to the filtrate, the pH was adjusted to 7 with NH4OH, and 5 g charcoal was added. The charcoal was removed by filtering through ashless paper which was then placed in a beaker and ashed at 600°C. After dissolving the cobalt oxide from the ash in 5N HNO3, cobalt content was determined by using AAS. To determine mg B12/lb feed, ppm cobalt in the feed is multiplied by 10.43. The sensitivity of the proposed procedure is 1 mg vitamin B12/lb. The procedure is rapid and precise, and results compare favorably with AOAC method 43.109.

Comparison of Methods for Determining Biuret in Urea

1979 ◽  
Vol 62 (1) ◽  
pp. 153-159
Author(s):  
Luis F Corominas ◽  
Victor M Boy ◽  
Manuel Guijosa
Keyword(s):  
Atomic Absorption ◽  
Spectrophotometric Determination ◽  
Atomic Absorption Spectrophotometry ◽  
International Organization ◽  
Comparison Of Methods ◽  
Definite Advantage ◽  
Absorption Spectrophotometry ◽  
Alternative Procedures ◽  
Aoac Method

Abstract The official first action AOAC method for the spectrophotometric determination of biuret in urea, 2.072—2.074, was compared with official first action AOAC method 2.C01-2.C03 (atomic absorption spectrophotometry), 2 simplified versions of 2.072-2.074, and modified versions of 2 alternative procedures of the International Organization for Standardization. Three synthetic urea samples (0.3, 1.4, and 3.0% biuret) and 1 commercial urea sample (1.0% biuret) were analyzed. The methods proved to be equivalent and none showed a definite advantage over 2.072-2.074. The purification of biuret and the interference by ammonia are also discussed.

Determination of Copper in Alfalfa

1971 ◽  
Vol 54 (4) ◽  
pp. 951-952
Author(s):  
A Donald Baker
Keyword(s):  
Sample Preparation ◽  
Atomic Absorption ◽  
Hydrofluoric Acid ◽  
Atomic Absorption Spectrophotometry ◽  
Absorption Spectrophotometry ◽  
Dry Ashing ◽  
Wet Ashing ◽  
Aoac Method ◽  
Determination Of Copper

Abstract Copper in alfalfa is determined by atomic absorption spectrophotometry after dry-ashing or wet-ashing of the sample. The method is as precise as and considerably more rapid than the present AOAC method. The standard deviations of the method for wet- and dry-ashing sample preparation were 0.56 and 0.97%, respectively. Recovery of copper from spiked samples was 96—100%. Removal of silica by hydrofluoric acid fuming was not necessary.

Determination of Minor Nutrients in Fertilizers by Atomic Absorption Spectrophotometry: Second Collaborative Study

1965 ◽  
Vol 48 (6) ◽  
pp. 1100-1103
Author(s):  
C H Mcbride
Keyword(s):  
Atomic Absorption ◽  
Collaborative Study ◽  
Atomic Absorption Spectrophotometry ◽  
Absorption Method ◽  
Atomic Absorption Method ◽  
Absorption Spectrophotometry ◽  
Minor Nutrients

Abstract The atomic absorption method studied last year was re-examined and extended to include calcium and sodium. The procedures were submitted to 16 collaborators for determination of Ca, Cu, Fe, Mg, Mn, Na, and Zn. Results for Ca and Na were discouraging; further study is recommended.

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