Tellurium as Catalyst in Semimicro Kjeldahl Method for Total Nitrogen Determination

1982 ◽  
Vol 65 (4) ◽  
pp. 786-790
Author(s):  
Christina F-H Liao
Keyword(s):  
Total Nitrogen ◽  
Organic Nitrogen ◽  
Complete Recovery ◽  
Nitrogen Compounds ◽  
Nitrogen Determination ◽  
Plant Soil ◽  
Clearing Time ◽  
Kjeldahl Digestion ◽  
Kjeldahl Method ◽  
Agricultural Materials

Abstract A modified semimicro Kjeldahl procedure is described for total nitrogen determination in agricultural materials and refractory organic nitrogen compounds, in which tellurium, alone or in combination with copper, is used as a catalyst. Tellurium alone is adequate for complete recovery of nitrogen from nicotinic acid if the acid:salt ratio is carefully controlled to nearly 1. However, when a mixture of tellurium and copper is used, complete nitrogen recovery could be obtained at a higher acidrsalt ratio. Use of a mixture also reduces clearing time when compared with copper alone in the Kjeldahl digestion. For samples containing nitrate, a Devarda's alloy (Cu:Al:Zn = 10:9:1) is proposed as a reducing agent in the pretreatment procedure to convert nitrate to ammonium in 6N H2SO4, with subsequent digestion of the sample by using a mixture of K2S04-catalyst and concentrated H2SO4. The proposed method is applicable for total nitrogen determination including NO3-N in plant, soil, and fertilizer samples.

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.

Zirconium Dioxide, A New Catalyst, in the Kjeldahl Method for Total Nitrogen Determination

1974 ◽  
Vol 57 (5) ◽  
pp. 1228-1230 ◽  
Author(s):  
William Glowa
Keyword(s):  
Total Nitrogen ◽  
Zirconium Dioxide ◽  
Mercuric Oxide ◽  
Cupric Sulfate ◽  
Nitrogen Determination ◽  
Mixed Catalyst ◽  
Kjeldahl Method

Abstract The standard Kjeldahl method for the determination of total nitrogen in fertilizers, feeds, foods, and beverages has been modified to eliminate the use of mercuric oxide, which is poisonous to the environment. A new mixed catalyst, consisting of 0.60 g cupric sulfate and 0.20 g zirconium dioxide in combination or 0.70 g zirconium dioxide alone, is recommended to replace the 0.70 g or more of mercuric oxide used in all official macro Kjeldahl methods.

NITROGEN DETERMINATION IN WHEAT LEAVES

1950 ◽  
Vol 28c (6) ◽  
pp. 745-753 ◽  
Author(s):  
D. W. A. Roberts
Keyword(s):  
Salicylic Acid ◽  
Organic Nitrogen ◽  
Nitrate Nitrogen ◽  
Soluble Nitrogen ◽  
Mercuric Oxide ◽  
Nitrogen Fractions ◽  
Nitrogen Determination ◽  
Satisfactory Method ◽  
Kjeldahl Method ◽  
Wheat Leaves

A survey of the more promising modifications of the Kjeldahl method for nitrogen determination indicates that the method using mercuric oxide as the catalyst as recommended by the Association of Official Agricultural Chemists is the most satisfactory. However small discrepancies were found when this method was applied to wheat leaves fractionated into soluble and protein (actually coagulable and indiffusible) nitrogen fractions. This method includes all the nitrate nitrogen in wheat leaves together with the organic nitrogen even when no pretreatment with salicylic acid is used. A simple and satisfactory method of separating coagulable and indiffusible nitrogen from soluble nitrogen in wheat leaves and seedlings is described.

scholarly journals Effect of peat samples drying on measured content of carbon and nitrogen fractions

2013 ◽  
Vol 64 (4) ◽  
pp. 130-134 ◽  
Author(s):  
Jerzy Jonczak
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Total Nitrogen ◽  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
Mineral Nitrogen ◽  
Nitrogen Compounds ◽  
Carbon And Nitrogen ◽  
Nitrogen Fractions ◽  
Initial Stage

Abstract The aim of the study was to compare the content of carbon and nitrogen fractions in fresh and dried samples of peat. The samples were extracted in 0.25 mol KCl·dm.-3, 0.25 mol H2SO4·dm.-3 and 2.5 mol H2SO4·dm.-3. Based on the extractions and analysis of total organic carbon (TOC) and total nitrogen (TN) following fractions of carbon and nitrogen were isolated: nonhydrolyzable carbon (NHC) and nitrogen (NHN), hardly hydrolyzable carbon (HHC) and nitrogen (HHN), easy hydrolyzable carbon (EHC) and nitrogen (EHN), dissolved organic nitrogen (DON), and its ammonium (NH4.-N) and nitrate (NO3.-N) form. Large differences between fresh and dried samples were observed in the content of some analyzed fractions . especially NO3.-N, NH4.-N, DON and HHC. 1.6.3.5 times higher concentrations of NO3.-N were observed in dry samples in comparison with fresh. In dried samples were also observed higher concentrations of NH4.-N and DON. In general lower concentrations of EHN, NHN, HHC and higher of HHN and EHC were observed in dried samples in comparison to fresh. Higher content of mineral nitrogen, as well as DON and DOC in dried samples, is probably an effect of mineralization of carbon and nitrogen compounds during initial stage of drying. The obtained data suggest, that the content of NO3.-N, NH4.-N, DON and EHC analyzed in dried samples of peat is overestimated. Extractions of the fractions from organic samples should be done based on fresh samples, just after sampling

Comparison of the Automatic Dumas (Coleman Model 29A Nitrogen Analyzer II) and Kjeldahl Methods for the Determination of Total Nitrogen in Agricultural Materials

1968 ◽  
Vol 51 (1) ◽  
pp. 216-219 ◽  
Author(s):  
G F Morris ◽  
R B Carson ◽  
D A Shearer ◽  
W T Jopkiewicz
Keyword(s):  
Experimental Data ◽  
Standard Deviation ◽  
Total Nitrogen ◽  
Statistical Evaluation ◽  
Kjeldahl Method ◽  
Agricultural Materials ◽  
Combustion Technique

Abstract A wide variety of agricultural materials were analyzed for total nitrogen by the Kjeldahl and automatic Dumas methods. The recoveries of nitrogen compared favorably by both methods when a catalystassisted combustion technique was used in the automatic Dumas method. Statistical evaluation of the experimental data, as measured by standard deviation, showed that the Kjeldahl method was generally more precise than the automatic Dumas method

scholarly journals Research on the Transformation of Nitrogen during Hydrothermal Carbonization of Sludge

2018 ◽  
Vol 175 ◽  
pp. 01019
Author(s):  
Ying Sun ◽  
Qian Yang
Keyword(s):  
Thermal Decomposition ◽  
Liquid Phase ◽  
Total Nitrogen ◽  
Organic Nitrogen ◽  
Inorganic Nitrogen ◽  
Hydrothermal Carbonization ◽  
Ammonia Nitrogen ◽  
Carbonization Temperature ◽  
Nitrogen Compounds

The nitrogen in the sludge mainly exists in the form of inorganic nitrogen and organic nitrogen.In this paper, the transformation of nitrogen during the hydrothermal carbonization of sludge was studied.The results showed that during the hydrothermal carbonization of the sludge, both the total nitrogen and theinorganic nitrogen in hydrochar decrease with the increase of the carbonization temperature. The reason isthat part of the inorganic nitrogen compounds in the sludge undergoes thermal decomposition to releaseNH3, and some organic nitrogen will be hydrolyzed to produce ammonia nitrogen into the liquid phase.

Studies on soil organic matter: Part I. The chemical nature of soil organic nitrogen

1949 ◽  
Vol 39 (2) ◽  
pp. 183-193 ◽  
Author(s):  
J. M. Bremner
Keyword(s):  
Amino Acids ◽  
Acid Hydrolysis ◽  
Total Nitrogen ◽  
Organic Nitrogen ◽  
Chemical Nature ◽  
Nitrogen Compounds ◽  
Soil Organic Nitrogen ◽  
Reducing Conditions ◽  
Nitrogen Contents ◽  
Hydrolysis Of

1. The acid hydrolysis of six soils with nitrogen contents ranging from 0·1 to 2·38% has been studied by determining the amounts of ammonia-, humin- and α-amino-N present in the soil hydrolysates after various periods of hydrolysis.2. Under the conditions of hydrolysis employed (3 ml. of 6N-HCl/g. soil) the period required for maximum liberation of amino-acids from the soils was about 12 hr. 24·2–37·1% of the total-nitrogen of the soils examined was liberated as α-amino-N in this period. Further hydrolysis led to destruction of amino-acids. Similar amounts of α-amino-N were liberated by hydrolysis of the soils with alkali (5N-NaOH).3. From 69 to 87% of the total-nitrogen of the soils was brought into solution by acid hydrolysis; the amount dissolved by hydrolysing with alkali or with alkali under reducing conditions (alkalistannite) was not significantly different. It is concluded that most of the insoluble-nitrogen found after acid hydrolysis is not derived from protein material, and it is suggested that some of this nitrogen is in the form of heterocyclic nitrogen compounds.

scholarly journals Dynamics of mineral nitrogen compounds in the waters of the Dniester River

2021 ◽  
Author(s):  
Petru Ciorba ◽  
◽  
Elena Zubcov ◽  
Nina Bagrin ◽  
Liliana Teodorof ◽  
...  
Keyword(s):  
Total Nitrogen ◽  
Water Samples ◽  
Seasonal Dynamics ◽  
Organic Nitrogen ◽  
Mineral Nitrogen ◽  
Ion Concentration ◽  
Ammonium Ion ◽  
Nitrogen Compounds ◽  
Ammonium Ions ◽  
Nitrate Ions

This article presents the results of studying the content of mineral (ammonium ions, nitrites and nitrates) and organic nitrogen compounds in water samples collected from the Dniester river in 2020. In the study are examines the seasonal dynamics of the forms of mineral nitrogen, total nitrogen and the correlation between organic and mineral nitrogen. Limits of ammonium ion concentration in the Dniester river varied between 0.002 mg N/l and 0.93 mg N/l, nitrite ions 0.002 mg N/l and 0.05 mg N/l, nitrate ions 0.002 mg N/l - 1.36 mg N/l.

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