An Unforeseen Problem in the Use of Kel-Paks

1968 ◽  
Vol 51 (6) ◽  
pp. 1290-1295
Author(s):  
T C Woodis ◽  
J A Brabson ◽  
W G Burch
Keyword(s):  
Salicylic Acid ◽  
Nicotinic Acid ◽  
Organic Compounds ◽  
Total Nitrogen ◽  
Ammoniacal Nitrogen ◽  
Powder Method ◽  
Catalyst Powder ◽  
Possible Cause ◽  
Digestion Step

Abstract In Kjeldahl methods for the determination of nitrogen in fertilizers, the digestion temperature must be above 370°C to mineralize the nitrogen in refractory organic compounds such as nicotinic acid. In total nitrogen determinations by the Raney catalyst powder method, temperatures during the digestion step were investigated as a possible cause of occasional low results. Decomposition of the polyethylene envelopes of Kel-Paks in the presence of salts of metallic reductants caused rapid fluctuations and excessive rise in temperature with consequent loss of ammoniacal nitrogen. Complete Kel-Paks can be used without difficulty in methods such as 2.044 (for nitrate-free samples) or 2.045 (salicylic acid) that do not use metallic reductants, but only the contents of the Kel-Paks without the envelopes should be used when Raney catalyst or chromium powders have been used to reduce nitrates.

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.

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.

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.

scholarly journals Determination of rate parameter for kinetics of nitrification

2018 ◽  
Vol 4 (2) ◽  
pp. 234
Author(s):  
S R Juliastuti ◽  
J Baeyens ◽  
C Creemers ◽  
J Degreve
Keyword(s):  
Oxygen Uptake ◽  
Organic Compounds ◽  
Total Nitrogen ◽  
Uptake Rate ◽  
Oxygen Uptake Rate ◽  
Inhibitory Effect ◽  
Rate Parameter ◽  
Autotrophic Biomass ◽  
Kinetics Of

Determination of rate parameter for kinetics of nitrification The nitrification process is the bottleneck step in the total nitrogen removal. The formation of nitrate is considered as the rate limiting step in the whole process and its kinetics determine the design of the nitrification reactor. Heavy metals (Zn2+ and Cu2+) and different organic compounds are used as micropollutants. These kinetics were experimentally measured by respirometry. In line with the aim of the paper, the experimental investigation are conducted to develop design equations to describe kinetic rate relationships under optimum conditions, study the parameter influence such as pH and inhibition by reaction intermediates and inhibition by external pollutants. Results demonstrate that the maximum value of the specific growth rate of autotrophic biomass() is 1.02 day at pH=7 and decreases at pH 7.5; inhibition occurs at substrate (NH4) concentrations in excess of 15 mg N/l; inhibition occurs at increasing concentrations of NO –N and Cu2+ has more pronounced inhibitory effect than Zn2+. The inhibitory effect of organic compounds are listed as the Chlorobenzene > Trichloroethylene> Phenol> Ethyl benzene; the experimental oxygen uptake rate (OUR)-test results the autotrophic kinetic parameter values, which can be used in design equations. Keywords: Respirometry,  Autotrophic Biomass,  Nitrification, Oxygen Uptake Rate Abstrak Proses nitrifikasi merupakan langkah penting pada penurunan kadar total nitrogen. Pembentukan nitrat dianggap sebagai tahap pembatas kecepatan reaksi pada keseluruhan proses dan kinetikanya menentukan perancangan dari bagian proses nitrifikasi. Logam berat (Zn2+ dan Cu2+) dan berbagai jenis komponen organik digunakan sebagai mikropolutan. Kinetika ini secara eksperimental diukur menggunakan respirometer. Tujuan penelitian adalah mengembangkan persamaan perancangan yang menggambarkan hubungan laju kinetika pada kondisi optimum, studi pengaruh parameter seperti pH, inhibisi karena reaksi intermediat, dan inhibisi oleh polutan dari luar. Hasil penelitian ditunjukkan sebagai berikut: harga laju pertumbuhan  biomasa autotrof maksimum spesifik  adalah 1,02 hari-1 pada pH=7 dan menurun pada pH 7,5; inhibisi terjadi pada konsentrasi substrat (NH4+) lebih besar dari 15 mg N/l; inhibisi terjadi pada peningkatan  konsentrasi NO -N ;Cu2+  lebih dikenal sebagai penyebab  inhibisi  daripada Zn2+. Efek inhibisi dari komponen organik di daftar mulai dari Chlorobenzene sampai Ethylbenzen. Tes OUR menghasilkan harga parameter kinetika yang dapat dipakai pad apersamaan perencanaan  lumpur aktif nitrifikasi. Kata Kunci: Respirometer, BiomasaAutotrof, Nitrifikasi, Laju Kenaikan Oksigen

Determination of Ammoniacal and Total Nitrogen in Fertilizers by Ammonia-Selective Electrode

1984 ◽  
Vol 67 (5) ◽  
pp. 890-892
Author(s):  
Roberto A Navarro ◽  
Pedro Rojas
Keyword(s):  
Tartaric Acid ◽  
Magnesium Oxide ◽  
Total Nitrogen ◽  
Ammoniacal Nitrogen ◽  
Selective Electrode ◽  
Digestion Procedure ◽  
Acid Recovery ◽  
Aoac Official ◽  
Good For

Abstract A method was studied for determining ammoniacal nitrogen in fertilizers by using an ammonia-selective electrode. Recovery for the method was evaluated with synthetic samples, and the method was also compared with the magnesium oxide method by analyzing 3 Magruder Check Samples. The method was adapted to determine total nitrogen in fertilizers by using the digestion procedure of the modified comprehensive nitrogen method and eliminating metal interferences by forming soluble complexes with tartaric acid. Recovery was evaluated and a comparison with AOAC official methods was made by performing a /-test on results for 3 Magruder Check Samples. Recoveries were good for determinations of both ammoniacal and total nitrogen by the method described, and results were not significantly different from those for AOAC methods.

A New Approach to the Raney Catalyst Powder Method for Total Nitrogen in Fertilizers

1969 ◽  
Vol 52 (1) ◽  
pp. 23-30 ◽  
Author(s):  
J A Brabson ◽  
T C Woodis
Keyword(s):  
Sulfuric Acid ◽  
Refractory Compound ◽  
Potassium Sulfate ◽  
Dilute Solution ◽  
Commercial Alloy ◽  
New Approach ◽  
Powder Method ◽  
Catalyst Powder ◽  
Time Required

Abstract Further study of the Raney catalyst powder method for the determination of nitrogen in fertilizers established conditions in which the commercial alloy containing 50% Ni and 50% Al was a more efficient reductant for nitrates than an experimental alloy that contained 10% Co. Errors in measurement were decreased, accuracy was increased, and time was saved by adding all the sulfuric acid and part of the potassium sulfate as a single dilute solution and heating the mixture immediately to promote the reduction. Changes in the amounts of reagents, including use of the contents of a Kcl-Pak without the polyethylene envelope, resulted in smoother and more effective Kjeldahl digestions. The method is “rugged” and is equally applicable to the refractory compound nicotinic acid, mixtures of nitrates and organic materials, and the simplest inorganic fertilizers. The time required for an analysis can be further shortened by using “Autopettes” for dispensing the standard acid and a “Titralyzer” for back titrations.

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.

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.

Ammonia-Selective Electrode Determination of Nitrogen in Fertilizers

1981 ◽  
Vol 64 (5) ◽  
pp. 1096-1099
Author(s):  
Victor M Boy ◽  
Manuel Guijosa
Keyword(s):  
Magnesium Oxide ◽  
Total Nitrogen ◽  
Ammoniacal Nitrogen ◽  
Selective Electrode ◽  
Nitrogen Determination ◽  
Accuracy And Precision ◽  
Routine Work ◽  
Electrode Method ◽  
Aoac Official

Abstract The official AOAC magnesium oxide method (MOM), 2.065, for determining ammoniacal nitrogen in fertilizers not containing urea was compared with an alternative ammonia-selective electrode method (ASEM-1). Likewise, the official AOAC Raney powder method (RPM), 2.063-2.064, for determining total nitrogen in fertilizers, except nitric phosphates containing nonsulfate S, was compared with an ammonia- selective electrode method (ASEM-2). Each comparison included 6 samples. For ammoniacal nitrogen determination, MOM and ASEM-1 showed equivalent precision, although significant statistical differences were obtained in average values for the majority of samples. For total nitrogen determination, RPM and ASEM-2 showed equivalent precision, although significant statistical differences were obtained in 3 samples. The AOAC official methods showed better accuracy than ASEM-1 and ASEM-2. However, the accuracy and precision of ASEM-1 for ammoniacal nitrogen is suitable for routine work.

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.

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