Food and feed products. General guidelines for determination of nitrogen by Kjeldahl method

2009 ◽  
Keyword(s):  
Food And Feed ◽  
Kjeldahl Method

Total protein determined in human breast milk by use of coomassie brilliant blue and centrifugal analysis.

1989 ◽  
Vol 35 (10) ◽  
pp. 2127-2129 ◽  
Author(s):  
Y Bergqvist ◽  
L Karlsson ◽  
L Fohlin
Keyword(s):  
Breast Milk ◽  
Total Protein ◽  
Brilliant Blue ◽  
Human Breast Milk ◽  
Human Breast ◽  
Simple Method ◽  
Coomassie Brilliant Blue ◽  
Kjeldahl Method ◽  
Coomassie Brilliant

Abstract This simple method of centrifugal analysis for total protein in human breast milk is based on the change in the wavelength of the absorbance maximum of Coomassie Brilliant Blue G-250 when the dye is bound to protein. Within-run and between-day CVs were 3.8% and 4.8%, respectively. Compared with a micro-Kjeldahl method for determination of total nitrogen, the coefficient of correlation was 0.99.

scholarly journals Herbicides from the group of nitrodiphenyl ethers: applications in Ukraine, control methods, methods for determination of oxifluorphene residues in soybean grain and oil

2021 ◽  
Vol 20 (66) ◽  
pp. 15-23
Author(s):  
Yu Baranov ◽  
◽  
V Demchenko ◽  
Ie Zajets ◽  
S Olszewski ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Selective Extraction ◽  
Agricultural Products ◽  
Gas Liquid Chromatography ◽  
Control Methods ◽  
Liquid Chromatography Mass Spectrometry ◽  
Analytical Validation ◽  
Regulatory Requirements ◽  
Food And Feed

A review of analytical methods for the determination of herbicide residues from the group of nitrodiphenyl ethers in the environment and agricultural products, developed and validated a method for oxyfluorfen determination in soybean grain and oil method GC/ECD, which meets regulatory requirements and solves the problem of toxicant control in the above matrices. The developed method uses modern methods of sample preparation, identification and quantification of oxyfluorfen (selective extraction, capillary gas-liquid chromatography (GC/ECD GC/MS). The method is validated according to EU requirements) (SANTE/12682/2019 quality control and analytical validation procedures for pesticide residues analysis in food and feed). Key words: gas-liquid chromatography, mass spectrometry, herbicides, nitrodiphenyl ethers, control, residual amounts.

Investigations of the Kjeldahl Method For the Determination of Nitrogen

1919 ◽  
Vol 3 (2) ◽  
pp. 218-220
Author(s):  
I K Phelps ◽  
H W Daudt
Keyword(s):  
Kjeldahl Method

Generic Combustion Method for Determination of Crude Protein in Feeds: Collaborative Study

1989 ◽  
Vol 72 (5) ◽  
pp. 770-774 ◽  
Author(s):  
Rose A Sweeney
Keyword(s):  
Crude Protein ◽  
Collaborative Study ◽  
Combustion Method ◽  
Performance Requirements ◽  
General Terms ◽  
Relative Standard ◽  
Kjeldahl Method ◽  
Standard Deviations ◽  
And Performance

Abstract Nine laboratories participated in a collaborative study on determination of crude protein in animal feeds to compare a generically described combustion method with the AOAC mercury catalyst Kjeldahl method (7.015). The combustion method was written in general terms of method principle, apparatus specifications, and performance requirements. The sample set comprised closely matched pairs of feed ingredients and mixed products ranging from 10 to 90% protein. Ten pairs ground to 0.5 mm were the focus of the study; 4 pairs were ground to 1.0 mm for comparison. Nicotinic acid and lysine monohydrochloride were included as standards. Collaborators were instructed to report their results for performance checks using materials supplied. Only one laboratory failed to meet the proposed limits. Seven laboratories used the LECO Model FP-228 analyzer and 2 used the LECO CHN 600 analyzer. For the 0.5 mm pairs, repeatability standard deviations (sr) ranged from 0.09 to 0.58 for the Kjeldahl method and from 0.14 to 0.33 for the combustion method, with a pooled sr value of 0.28 and relative standard deviation (RSDr) of 0.59%. Reproducibility standard deviations (SR) ranged from 0.23 to 0.86 (Kjeldahl) and from 0.30 to 0.61 (combustion), with a pooled sR value of 0.52 and RSDR of 1.10%. Grand means for the samples ground to 0.5 mm were 47.65% protein by the combustion method and 47.41% protein by the Kjeldahl method. For samples ground to 1.0 mm, corresponding values were 31.82 and 31.50% protein. The generic combustion method has been approved interim official first action.

scholarly journals XXXIII.—I. On the Estimation of Carbon in Organic Substances by the Kjeldahl Method. II. Its Application to the Analysis of Potable Waters

1895 ◽  
Vol 37 (4) ◽  
pp. 743-757
Author(s):  
Charles Hunter Stewart
Keyword(s):  
Accurate Method ◽  
Great Accuracy ◽  
Organic Substances ◽  
Applied Chemistry ◽  
Carbon And Nitrogen ◽  
Kjeldahl Method ◽  
The Will ◽  
Time Required

An easy and yet accurate method of determining carbon and nitrogen in organic substances has long been a desideratum, especially among those engaged in the application of chemistry to biological, hygienic, and agricultural questions. For the determination of nitrogen the method of Dumas, with its numerous modifications, is still the only one applicable in all cases, but the time required for it, and the manipulative dexterity necessary, has prevented its wide application for the above-named purposes. The method of Will and Varrentrap, though less generally applicable, is easier, and, until the publication of Kjeldahl's method, was most frequently used in applied chemistry. Kjeldahl claims for his method the same applicability and as great accuracy as the Will and Varrentrap method, with the added advantage of greater ease in working.

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