Total Nitrogen in Fertilizers

1968 ◽  
Vol 51 (4) ◽  
pp. 851-857
Author(s):  
Paul R Rexroad ◽  
Gary F Krause
Keyword(s):  
Total Nitrogen ◽  
Collaborative Study ◽  
New Method ◽  
Official Method ◽  
Powder Method ◽  
Catalyst Powder

Abstract A three-laboratory collaborative study was made of the comprehensive nitrogen method and the new Raney catalyst powder method for total nitrogen in fertilizers. Both methods worked quite well and, with minor modifications, they should provide the basis for a broader collaborative stvidy to provide an official method for total nitrogen in fertilizer applicable to all samples. The limitations of method 2.045 are reviewed and a rephrasing of the official applications of the method is recommended. Further work is recommended toward adoption of a new method and possible deletions or change of status in current official methods.

Total Nitrogen in Fertilizer: Collaborative Study

1978 ◽  
Vol 61 (2) ◽  
pp. 299-306
Author(s):  
Paul R Rexroad ◽  
Gary F Krause
Keyword(s):  
Total Nitrogen ◽  
Collaborative Study ◽  
Oxidation Catalyst ◽  
Official Method ◽  
Probability Level ◽  
Sulfate Sulfur ◽  
Powder Method ◽  
Modified Method ◽  
Accuracy And Precision ◽  
Cent Nitrogen

Abstract A modified comprehensive nitrogen method, using 0.4 g C11SO4 as catalyst, is presented. This method plus a modified Raney powder method (mercury-free) with no metallic oxidation catalyst are compared with the AOAC comprehensive nitrogen method. Results from 19 collaborating laboratories for 11 samples are evaluated. The modified Raney method gave significantly low results on 2 samples: 21-7-14 (nitric phosphates-non-sulfate sulfur) and tryptophan. The results for the average per cent nitrogen for 11 samples from the modified comprehensive nitrogen method were comparable to those from the official method at the 95 % probability level; the overall pooled standard deviations were also similar. In this collaborative study, the modified method (with copper) was equal in accuracy and precision to the official method (with mercury). The modified comprehensive nitrogen method has been adopted as official first action.

Determination of Total Nitrogen in Fertilizers

1965 ◽  
Vol 48 (2) ◽  
pp. 401-406
Author(s):  
H A Davis ◽  
W E Urban
Keyword(s):  
Nickel Catalyst ◽  
Raney Nickel ◽  
Total Nitrogen ◽  
Official Method ◽  
Chromium Powder ◽  
Powder Method ◽  
Raney Nickel Catalyst ◽  
Catalyst Powder ◽  
Iron Chromium

Abstract Five methods, AOAC 2.037, 2.039, modified reduced iron, chromium powder, and Raney nickel catalyst powder for the determination of total nitrogen in fertilizers, were submitted to collaborators for study. Twelve laboratories participated and completed the work. No one method was “best.” The modified reduced iron, chromium powder, and Raney nickel catalyst powder methods gave essentially equal results, but the chromium powder method is favored for case of operation and time required. However, if considerable organic matter and nitrate are present in a sample, satisfactory results may not be obtained. The analyst should select the official method best suited to the makeup of the sample. It is recommended that the chromium powder method he adopted as official, first action, and that study be continued with the modified reduced iron and Raney nickel catalyst methods, including helpful proposals in developing a method that may be applicable to all fertilizers.

Total Nitrogen Methods—Applicable to All Fertilizer Samples

1970 ◽  
Vol 53 (3) ◽  
pp. 450-456
Author(s):  
Paul R Rexroad ◽  
Gary F Krause
Keyword(s):  
Salicylic Acid ◽  
Total Nitrogen ◽  
Collaborative Study ◽  
Official Method ◽  
Chromium Powder ◽  
Powder Method ◽  
New Methods

Abstract An extensive collaborative study was conducted to evaluate a comprehensive nitrogen method and a Raney powder method for acceptance as official methods. Twenty-nine laboratories participated; 10 samples were used and the new methods were compared to the official method, 2.045 (sulfuric-salicylic acid). Evaluation of the data and overall consideration lead to the recommendation that both new methods be adopted as official. It is recommended that 2.047 (reduced iron) and 2.049 (chromium powder) be deleted as official methods.

How Rugged Are Our Nitrogen Methods?

1965 ◽  
Vol 48 (3) ◽  
pp. 501-507
Author(s):  
W G Burgh ◽  
J A Brabson
Keyword(s):  
Salicylic Acid ◽  
Standard Deviation ◽  
Total Nitrogen ◽  
Reduction Method ◽  
Official Method ◽  
Powder Method ◽  
Catalyst Powder ◽  
Time Of Reaction

Abstract Youden’s ruggedness test was made of two official methods and four more recent methods for the determination of total nitrogen in fertilizers containing nitrates. Among the variables tested were amounts of nitrogen and reductant, effect of chloride, and time of reaction of reductant. Official method 2.039 (reduced-iron) failed the test. In order of increasing standard deviation, the five methods that passed the test were the chromous reduction method, Raney-catalyst-powder method, official method 2.037 (salicylic acid), improved reduced-iron method, and the chromiumpowder method.

Collaborative Study of a New Method for Extraction of Light Filth from Reconditioned (Coarsely Ground) Nutmeg

1971 ◽  
Vol 54 (3) ◽  
pp. 575-578
Author(s):  
Alberto W Vazquez
Keyword(s):  
Collaborative Study ◽  
Mineral Oil ◽  
New Method ◽  
Official Method ◽  
Collaborative Testing

Abstract A new method has been developed for extraction of light filth from coarsely ground nutmeg. Nutmeg tissue is defatted by 3 successive 10 min extractions with boiling CHCI3, after which the solvent is removed by aspiration and an isopropanol rinse. Following sieving on a No. 230 sieve and a brief deaeration and hydrolysis step in acidified boiling 60% ethanol-CaCl2, light filth elements are extracted with mineral oil from the 60% ethanol-CaCl2 mixture. Collaborative testing of the proposed method yielded satisfactory recoveries of added light filth elements. The official method for ground spices, 40.106(b), was compared in a collaborative study with the proposed method for the analysis of ground nutmeg and mace. Results were encouraging, but further study is indicated. The method as described for reconditioned nutmeg has been adopted as official first action.

Extraction of Light Filth from Canned Green Leafy Vegetables: Collaborative Study

1979 ◽  
Vol 62 (3) ◽  
pp. 600-601
Author(s):  
Russell G Dent ◽  
Jack L Boese
Keyword(s):  
Plant Material ◽  
Collaborative Study ◽  
Excessive Amount ◽  
Leafy Vegetables ◽  
New Method ◽  
Official Method ◽  
Green Leafy Vegetables

Abstract The official first action method, 44.108, for the extraction of light filth from whole or chopped canned greens specifies a waterheptane flotation that results in the flotation of an excessive amount of interfering plant material and in low recoveries. A new method has been developed using a 40% isopropanol-watermineral oil flotation. The new method yielded a decreased amount of plant material and 84.9% recovery of the aphid spike compared with 42.5% recovery of the spike by the official method. The new method has been adopted as official first action to replace the existing method, except for broccoli.

An Improved Raney Catalyst Powder Method for Determination of Nitrogen in Fertilizers

1965 ◽  
Vol 48 (6) ◽  
pp. 1111-1115
Author(s):  
W G Burch ◽  
J A Brabson
Keyword(s):  
Sulfuric Acid ◽  
Total Nitrogen ◽  
Organic Nitrogen ◽  
Nitrogen Compounds ◽  
Test Results ◽  
Powder Method ◽  
Catalyst Powder ◽  
Good Agreement

Abstract With a Raney catalyst powder containing 10% Co, 40%; Ni, and 50% Al, nitrates are reduced to ammonia in 8N sulfuric acid in 10 minutes. Neither chlorides nor organic nitrogen compounds interfere with the reduction, and the reduction passed Youden’s ruggedness test. Results of analyses of fertilizers for total nitrogen that included reduction with the powder were in good agreement with those of accepted methods.

Collaborative Study of a New Method for the Extraction of Light Filth from Ground Coffee

1972 ◽  
Vol 55 (1) ◽  
pp. 57-59
Author(s):  
Joel J Thrasher
Keyword(s):  
Hydrogen Peroxide ◽  
Carbon Tetrachloride ◽  
Collaborative Study ◽  
Mineral Oil ◽  
New Method ◽  
Official Method ◽  
Peroxide Bleaching ◽  
Filter Papers ◽  
Analytical Time ◽  
Ground Coffee

Abstract A collaborative study has been completed on a new method for light filth in ground coffee. The sample is defatted with chloroform, dried, and boiled in water; isopropanol is added and the sample is boiled again. Light filth is trapped off with mineral oil from a hot solution. The method yields better recoveries of insect fragments and rodent hairs than the official method. Other advantages are less analytical time, cleaner filter papers, and elimination of the use of carbon tetrachloride. It is recommended that the method be adopted as official first action to replace 40.007(b) for the isolation of light filth from ground coffee and that the hydrogen peroxide bleaching technique described earlier be adopted as a procedure to replace the sodium hypochlorite technique described in 40.006.

Total Solids in Processed Vegetables

1964 ◽  
Vol 47 (3) ◽  
pp. 492-500
Author(s):  
Frank C Lamb
Keyword(s):  
Sample Size ◽  
Diatomaceous Earth ◽  
Collaborative Study ◽  
New Method ◽  
Official Method ◽  
Total Solids ◽  
Sources Of Error ◽  
Vegetable Products ◽  
The Individual

Abstract A method was developed for total solids in processed vegetable products, involving diluting with diatomaceous earth, predrying by any of three procedures, and final drying in vacuo for 2 hours at 69-71°. The new method was found to give lower results than the official method on all products tested except pork and beans and baked beans. In a collaborative study by 17 analysts in 9 laboratories, the new method was slightly more precise than the official method, but its main advantage was in providing greater flexibility in sample size and predrying conditions, and in requiring less time for an analysis. The major sources of error in both methods appeared to be deficiencies in the vacuum ovens used and lack of skill of the individual analysts.

Mercury-Free Raney Catalyst Method for Total Nitrogen in Fertilizers

1974 ◽  
Vol 57 (1) ◽  
pp. 10-13
Author(s):  
Frank J Johnson ◽  
Terry C Woodis ◽  
James M Cummings
Keyword(s):  
Total Nitrogen ◽  
Digestion Time ◽  
Sulfate Sulfur ◽  
Powder Method ◽  
Modified Method ◽  
Catalyst Powder ◽  
Considerable Range

Abstract The original Raney catalyst powder method for total nitrogen was shown not to be applicable to nitric phosphates containing non-sulfate sulfur. Interference by the non-sulfate sulfur was eliminated by the addition of morin, a mordant dye, before the reduction. The method was modified further by omitting HgO, a possible pollutant, from the digestion and by shortening the digestion time. The modified method is highly rugged for a considerable range of fertilizer materials.

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