Comparison of Tellurium and Selenium as Catalysts for Kjeldahl Digestion

1949 ◽  
Vol 21 (8) ◽  
pp. 1012-1013 ◽  
Author(s):  
R. B. Bradstreet
Keyword(s):  
Kjeldahl Digestion

KJELDAHL DIGESTION AS SILVER SALT OF CYANO COMPOUNDS

1973 ◽  
Vol 2 (11) ◽  
pp. 1177-1180
Author(s):  
Michiko Shirai
Keyword(s):  
Silver Salt ◽  
Kjeldahl Digestion ◽  
Cyano Compounds

CuSO4-TiO2 as Kjeldahl Digestion Catalyst in Manual Determination of Crude Protein in Animal Feeds

1986 ◽  
Vol 69 (4) ◽  
pp. 664-666
Author(s):  
Peter F Kane
Keyword(s):  
Standard Deviation ◽  
Crude Protein ◽  
T Test ◽  
Environmental Concerns ◽  
Animal Feeds ◽  
Significant Difference ◽  
Kjeldahl Digestion ◽  
Student’S T ◽  
Student’S T Test

Abstract The official AOAC manual Kjeldahl methods for determining crude protein in animal feeds have several disadvantages. For the HgO catalyst method, there are environmental concerns and a lengthy digestion. For the CuS04 catalyst method, the digestion period is shorter, but still 90 min. A different catalyst combination, CuS04-Ti02, makes 40 min digestion feasible. Comparison of these catalysts on a group of representative feeds resulted in a mean difference, Cu-Ti minus HgO, of 0.034% protein. Standard deviation of the differences was 0.36. A Student’s t-test showed no significant difference. The method will be collaboratively studied.

Diagnostic Data Evaluation. Part III. Collaborative Study Evaluation: Standard Deviation Considered To Be A Constant

1990 ◽  
Vol 73 (3) ◽  
pp. 411-414
Author(s):  
Anthony J Malanoski
Keyword(s):  
Crude Protein ◽  
Collaborative Study ◽  
Performance Standard ◽  
Evaluation Standard ◽  
Pork Sausage ◽  
Sample Weights ◽  
Study Evaluation ◽  
Analyst Bias ◽  
Kjeldahl Digestion ◽  
Standard Deviations

Abstract The diagnostic evaluation of the crude protein collaborative study Identified possible problems with a standardized Interval for the Kjeldahl digestion, with sample preparation, and with excess sample weights. The standard deviations for the ham and the beef samples cannot be considered to be representative of the method because of these problems. The standard deviations for the frankfurter and the pork sausage samples for all analysts met the performance standard of 0.24. There was no evidence of analyst bias.

scholarly journals Application of Sparging to the Automated Ion Selective Electrode Determination of Kjeldahl Nitrogen

1980 ◽  
Vol 63 (4) ◽  
pp. 931-936
Author(s):  
Ram B Roy ◽  
John Jansen ◽  
Michael Sahn
Keyword(s):  
Ion Selective Electrode ◽  
Selective Electrode ◽  
Ammonia Sensing ◽  
Automated Method ◽  
Significant Difference ◽  
Naoh Solution ◽  
Kjeldahl Digestion ◽  
Aoac Method ◽  
Kjeldahl Nitrogen

Abstract An automated method has been developed for the determination of total Kjeldahl nitrogen. Sample digests are mixed with a NaOH solution and allowed to make contact with air flowing at 1000 mL/min. The mixture enters the inlet of a heating bath maintained at 75°C. On exit, ammonia gas separates from a sparging vessel and is trapped as ammonium sulfate in a dilute H2SO4 solution. An aliquot of the acid solution is resampled and made alkaline to generate ammonia, which is measured by an ammonia sensing probe. A comparison of this procedure with AOAC method 7.025 shows that the procedure is accurate and that there is no statistically significant difference between them. This procedure introduces a new approach to eliminate the interfering species present in sample digests after Kjeldahl digestion for automated ion selective electrode measurements of ammonia. Thirty samples/h can be analyzed by this method.

More Powerful Peroxide Kjeldahl Digestion Method

1987 ◽  
Vol 70 (5) ◽  
pp. 783-787 ◽  
Author(s):  
Clifford C Hach ◽  
Brian K Bowden ◽  
Alan B Kopelove ◽  
Scott V Brayton
Keyword(s):  
Nicotinic Acid ◽  
Refractory Compound ◽  
Complete Recovery ◽  
Minimal Amount ◽  
Digestion Time ◽  
State Controller ◽  
Ammonia Recovery ◽  
Kjeldahl Digestion ◽  
Time Required ◽  
Kjeldahl Nitrogen

Abstract Enhanced ammonia recovery and a simplified method are described for a rapid Kjeldahl digestion using sulfuric acid and hydrogen peroxide as the sole digestion reagents. This micro procedure uses a Vigreux fractionating head fitted to a 100 mL volumetric flask and a hot plate with a solid-state controller. Continuous-flow peroxide addition is controlled by a capillary funnel, and fumes are evacuated through a side-arm vent leading to a water aspirator. Complete recovery of nitrogen from the refractory compound, nicotinic acid, is obtained with less than 10 min digestion. The described method reduces digestion time by 25-50% over the open-manifold peroxy method. A digestibility index (DI), scaled 0-10, establishes the difficulty of digestion for each sample and assigns values to compounds. A useful tool for determining the minimal amount of reagent and digestion time required, the DI assigns zero for compounds not needing digestion and 10 for nicotinic acid. Digested samples obtained from the described method are suitable for direct colorimetric analysis of many elements in addition to Kjeldahl nitrogen. Distillation of the digested sample is not required

Effect of Ferric Sulfate in Shortening Kjeldahl Digestion

1940 ◽  
Vol 12 (7) ◽  
pp. 396-399 ◽  
Author(s):  
F. M. Stubblefield ◽  
E. E. Deturk
Keyword(s):  
Ferric Sulfate ◽  
Kjeldahl Digestion
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