Determination methods of total nitrogen in foreign countries

Determination methods of total nitrogen in foreign countries, Total:189 items.

The international standard classification for "Determination methods of total nitrogen in foreign countries" includes: Fertilizers , Chemical reagents , Auxiliary materials and additives for plastics , Edible oils and fats. Oilseeds , Rubber , Inorganic chemicals in general , Metalliferous minerals , Coals .

The Chinese standard classification for "Determination methods of total nitrogen in foreign countries" includes: Chemical fertilizer and chemical soil conditioner , Chemical reagent in general , Carbon black , Basic standards and general methods on chemical fertilizers , Basic standards and general methods , Rubber products in general , Inorganic chemicals in general , Iron ore , Coal analysis methods , Soil and fertilizer in general .

Jilin Provincial Standard of the People's Republic of China

DB22/T 1932-2013 Determination method of total nitrogen content in peat (Kjeldahl method)

General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China

GB 609-1988 General method for the determination of total nitrogen content of chemical reagents
GB/T 6730.24-1986 Methods for chemical analysis of iron ores; The arsenazo 3 photometric method for the determination of rare earth elements content
GB/T 17767.1-2008 Determination of organic-inorganic compound fertilizers - Part 1: Total nitrogen content
GB/T 10722-2014 Carbon black—Determination of total and external surface area—Nitrogen adsorption test method
GB/T 2441.1-2001 Determination of urea-Determination of total nitrogen content
GB/T 609-1988 Chemical reagent-General method for the determination of total nitrogen
GB/T 23952-2009 Inorganic chemicals for industrial use—General method for the determination of total nitrogen content—Distillation-acid-base titrations method
GB/T 40723-2021 Rubber—Determination the contents of total sulfur and total nitrogen — Automatic analyser method
GB/T 609-2018 Chemical reagent—General method for the determination of total nitrogen
GB/T 9823-1988 Method for determination of total nitrogen content in oilseed residues
GB/T 2441.1-2008 Determination of urea - Part 1: Total nitrogen content
GB/T 609-2006 Chemical Reagent - General Method for the Determination of Total Nitrogen
GB/T 11894-1989 Water quality--Determination of total nitrogen--Alkaline potassium persulfate digestion-UV spectro photometric method
GB/T 19227-2008 Determination of nitrogen in coal
GB/T 10722-2003 Carbon black - Determination of total and external surface area by nitrogen adsorption
GB/T 609-2018(XG1-2024) Chemical Reagents General Method for Determination of Total Nitrogen

Group Standards of the People's Republic of China

T/GXAS 477-2023 Determination of total nitrogen content in sugarcane juice —sulphuric acid titrimetric method
T/QAS 071-2021 Determination of total nitrogen in brine Kjeldahl method
T/NAIA 044-2021 Urine Total Nitrogen Determination in Livestock Kjeldahl Method

Hebei Provincial Standard of the People's Republic of China

DB13/T 1224-2010 Determination method of total nitrogen in organic chemical products

Professional Standard - Environmental Protection

HJ 636-2012 Water quality. Determination of total nitrogen. Alkaline potassium persulfate digestion UV spectrophotometric method

Professional Standard - Urban Construction

CJ 26.27-1991 Municipal sewage water quality inspection method standard Determination of total nitrogen Titration method after distillation
CJ/T 77-1999 Municipal sewage.Determination of total nitrogen.Distillation and titration method

Professional Standard - Agriculture

SL/T 788.1-2019 Part 1: Determination of total nitrogen in water quality
NY/T 2542-2014 Fertilizers. Determination of total nitrogen nitrogen content

Gosstandart of Russia

GOST R 58596-2019 Soils. Methods for determination of total nitrogen
GOST 10671.4-2016 Reagents. Methods for determination of total nitrogen impurity
GOST 26715-1985 Organic fertilizers. Methods for determination of total nitrogen
GOST 26107-1984 Soils. Methods for determination of total nitrogen
GOST 34789-2021 Brewing products. Identification. Determination of mass concentration of total nitrogen by Kjeldahl method
GOST EN 15750-2016 Fertilizers. Determination of total nitrogen in fertilizers containing nitrogen only as nitric, ammoniacal and urea nitrogen by two different methods
GOST R 54216-2010 Solid biofuels. Determination of total content of carbon, hydrogen and nitrogen by instrumental methods
GOST 32985-2014 Solid biofuels. Determination of carbon, hydrogen and nitrogen by instrumental methods

Indonesia Standards

SNI 4146-2013 Method for determination of total nitrogen content in sediment by Kjeldahl titration method
SNI 19-1501-1989 Test methods for total nitrogen oxide in air

American Society for Testing and Materials (ASTM)

ASTM D6556-10 Standard Test Method for Carbon Black-Total and External Surface Area by Nitrogen Adsorption
ASTM D6556-04 Standard Test Method for Carbon Black-Total and External Surface Area by Nitrogen Adsorption
ASTM D6556-01a Standard Test Method for Carbon Black8212;Total and External Surface Area by Nitrogen Adsorption
ASTM D6556-00a Standard Test Method for Carbon Black8212;Total and External Surface Area by Nitrogen Adsorption
ASTM D6556-17 Standard Test Method for Carbon Black&x2014Total and External Surface Area by Nitrogen Adsorption
ASTM D6556-01 Standard Test Method for Carbon Black8212;Total and External Surface Area by Nitrogen Adsorption
ASTM D8001-16 Standard Test Method for Determination of Total Nitrogen, Total Kjeldahl Nitrogen by Calculation, and Total Phosphorus in Water, Wastewater by Ion Chromatography
ASTM D6556-07 Standard Test Method for Carbon Black-Total and External Surface Area by Nitrogen Adsorption
ASTM D8001-16e1 Standard Test Method for Determination of Total Nitrogen, Total Kjeldahl Nitrogen by Calculation, and Total Phosphorus in Water, Wastewater by Ion Chromatography
ASTM D8001-16(2024) Standard Test Method for Determination of Total Nitrogen, Total Kjeldahl Nitrogen by Calculation, and Total Phosphorus in Water, Wastewater by Ion Chromatography
ASTM D6556-03 Standard Test Method for Carbon Black8212;Total and External Surface Area by Nitrogen Adsorption
ASTM D3590-02 Standard Test Methods for Total Kjeldahl Nitrogen in Water
ASTM D6556-02 Standard Test Method for Carbon Black8212;Total and External Surface Area by Nitrogen Adsorption
ASTM D6556-02a Standard Test Method for Carbon Black8212;Total and External Surface Area by Nitrogen Adsorption
ASTM D3590-11 Standard Test Methods for Total Kjeldahl Nitrogen in Water
ASTM D3590-17 Standard Test Methods for Total Kjeldahl Nitrogen in Water
ASTM D6556-14 Standard Test Method for Carbon Blackmdash;Total and External Surface Area by Nitrogen Adsorption
ASTM D6556-21 Standard Test Method for Carbon Black—Total and External Surface Area by Nitrogen Adsorption
ASTM D6556-09 Standard Test Method for Carbon Black-Total and External Surface Area by Nitrogen Adsorption
ASTM D1013-93(1998) Standard Test Method for Determining Total Nitrogen in Resins and Plastics
ASTM D6556-16 Standard Test Method for Carbon Black&x2014Total and External Surface Area by Nitrogen Adsorption
ASTM D3228-22 Standard Test Method for Total Nitrogen in Lubricating Oils and Fuel Oils by Modified Kjeldahl Method
ASTM E258-67(2002) Standard Test Method for Total Nitrogen in Organic Materials by Modified Kjeldahl Method
ASTM E258-67(1996)e1 Standard Test Method for Total Nitrogen in Organic Materials by Modified Kjeldahl Method
ASTM D8083-16 Standard Test Method for Total Nitrogen, and Total Kjeldahl Nitrogen (TKN) by Calculation, in Water by High Temperature Catalytic Combustion and Chemiluminescence Detection
ASTM D8083-24 Standard Test Method for Total Nitrogen, and Total Kjeldahl Nitrogen (TKN) by Calculation, in Water by High Temperature Catalytic Combustion and Chemiluminescence Detection

British Standards Institution (BSI)

BS 7755-3.7:1995 Soil quality. Chemical methods. Determination of total nitrogen. Modified Kjeldahl method
BS 5551-4.1.3:1986 Fertilizers. Chemical analysis. Determination of nitrogen. Method for determination of total nitrogen content (titrimetric method after distillation)
BS DD CEN/TS 15750:2008 Fertilizers. Determination of total nitrogen in fertilizers containing nitrogen only as nitric, ammoniacal and urea nitrogen by two different methods
BS 4267-2:1988 Ammonium nitrate - Method for determination of total nitrogen content
BS 4267-2:1988(1999) Ammonium nitrate — Part 2 : Method for determination of total nitrogen content
BS EN 15750:2009 Fertilizers - Determination of total nitrogen in fertilizers containing nitrogen only as nitric, ammoniacal and urea nitrogen by two different methods
BS EN 15750:2010 Fertilizers. Determination of total nitrogen in fertilizers containing nitrogen only as nitric, ammoniacal and urea nitrogen by two different methods
BS DD ISO/TS 12902:2002 Solid mineral fuels. Determination of total carbon, hydrogen and nitrogen. Instrumental methods
BS ISO 6851:2001 Photography. Processing waste. Determination of total amino nitrogen (microdiffusion Kjeldahl method)
BS DD CEN/TS 15104:2005 Solid biofuels — Determination of total content of carbon, hydrogen and nitrogen — Instrumental methods
BS DD CEN/TS 15104:2006 Solid biofuels - Determination of total content of carbon, hydrogen and nitrogen - Instrumental methods
BS ISO 20620:2021 Fertilizers and soil conditioners. Determination of total nitrogen by combustion
25/30481931 DC BS ISO 19615 Meat and fish products - Determination of total volatile basic nitrogen - Semi-micro nitrogen determination method

Standard Association of Australia （SAA）

AS 1871.11:1976 List of methods for examination of waters Nitrogen (total Kjeldahl incl. ammoniacal)

Association Francaise de Normalisation

NF V04-211:1971 MILK. DETERMINATION OF TOTAL NITROGEN CONTENT. (KJELDAHL METHOD).
NF A06-555:2010 Steel - Determination of nitrogen content - Spectrophotometric method.
NF X31-111*NF ISO 11261:1995 Soil quality. Determination of total nitrogen. Modified kjeldahl method.
NF U42-151:1984 Fertilizers. Determination of total nitrogen content. Titrimetric method after distillation.
NF U42-503*NF EN 15750:2010 Fertilizers - Determination of total nitrogen in fertilizers containing nitrogen only as nitric, ammoniacal and urea nitrogen by two different methods
NF ISO 20620:2022 Fertilizers and amendments - Determination of total nitrogen by combustion
NF EN 15750:2010 Fertilizers - Determination of the total nitrogen content of fertilizers containing nitrogen only in nitric, ammoniacal and urea form, using two different methods
NF U42-147*NF EN 15561:2009 Fertilizers - Determination of total nitrogen in calcium cyanamide containing nitrate
NF U42-504*NF ISO 20620:2022 Fertilizers and soil conditioners - Determination of total nitrogen by combustion
NF EN 15478:2009 Fertilizers - Determination of total nitrogen in urea

PL-PKN

PN C04576 ArkusZ12-1973 Water and waste water Tests for nitrogenDetermination of total nitrogen of Kjeldahl

VN-TCVN

TCVN 6498-1999 Soil quality.Determination of total nitrogen.Modifierd Kejldahl method
TCVN 3705-1990 Aquatic products.Method for the determination of total nitrogen and protein content

Standards Norway

NS-EN 15750:2009 Fertilizers — Determination of total nitrogen in fertilizers containing nitrogen only as nitric, ammoniacal and urea nitrogen by two different methods
SN-CEN/TS 15750:2008 Fertilizers — Determination of total nitrogen in fertilizers containing nitrogen only as nitric, ammoniacal and urea nitrogen by two different methods
SN-CEN/TS 15104:2005 Solid biofuels — Determination of total content of carbon, hydrogen and nitrogen — Instrumental methods
NS-EN 15104:2011 Solid biofuels — Determination of total content of carbon, hydrogen and nitrogen — Instrumental methods
NS-EN 13716:2001 Surface active agents — Determination of total base nitrogen — Potentiometric titration
SN-CEN/TS 15478:2006 Fertilizers — Determination of total nitrogen in urea

CZ-CSN

CSN 65 4836-1983 Minerál fertilizers Methode for determination of total nitrogen content
CSN 68 4124-1980 Determination of small mounts of total nitrogen
CSN 58 0703-7-1999 Testing methods of dehydrated products and seasonings - Part 7: Determinaton of total nitrogen

Association of Official Analytical Chemists (AOAC)

AOAC 991.20 AOAC Official Method 991.20 Nitrogen (Total) in Milk Kjeldahl Methods
AOAC Official Method 2001.14 Determination of total nitrogen in cheese

Danish Standards Foundation

DANSK DS/EN 15750:2009 Fertilizers - Determination of total nitrogen in fertilizers containing nitrogen only as nitric, ammoniacal and urea nitrogen by two different methods
DS/EN 15750:2010 Fertilizers - Determination of total nitrogen in fertilizers containing nitrogen only as nitric, ammoniacal and urea nitrogen by two different methods
DANSK DS/ISO 29441:2010 Water quality - Determination of total nitrogen after UV digestion - Method using flow analysis (CFA and FIA) and spectrometric detection
DS/ISO 29441:2010 Water quality - Determination of total nitrogen after UV digestion - Method using flow analysis (CFA and FIA) and spectrometric detection
DANSK DS/CEN/TS 15104:2005 Solid biofuels - Determination of total content of carbon, hydrogen and nitrogen - Instrumental methods
DS/EN 13716:2002 Surface active agents - Determination of total base nitrogen - Potentiometric titration
DANSK DS/EN 15478:2009 Fertilizers - Determination of total nitrogen in urea
DANSK DS/EN 13716:2002 Surface active agents - Determination of total base nitrogen - Potentiometric titration

Swedish Institute for Standards

SS-ISO 11261:1996 Soil quality - Determination of total nitrogen - Modified Kjeldahl method
SS-EN 15750:2009 Fertilizers - Determination of total nitrogen in fertilizers containing nitrogen only as nitric, ammoniacal and urea nitrogen by two different methods
ISO 6851 Photography - Processing waste - Determination of total amino nitrogen (microdiffusion Kjeldahl method)
SS-EN 13716:2002 Surface active agents - Determination of total base nitrogen - Potentiometric titration
SS-EN 15478:2009 Fertilizers - Determination of total nitrogen in urea

Spanish Association for Standardization (UNE)

AENOR UNE-EN 15750:2010 Fertilizers - Determination of total nitrogen in fertilizers containing nitrogen only as nitric, ammoniacal and urea nitrogen by two different methods
UNE 34080:1974 ANALYSIS METHODS FOR CHOCOLATES. DETERMINATION OF TOTAL NITROGEN. (PROTEINS).
UNE 77318:2001 Soil quality. Determination of total nitrogen. Modified Kjeldahl method.
UNE-EN 15750:2010 Fertilizers - Determination of total nitrogen in fertilizers containing nitrogen only as nitric, ammoniacal and urea nitrogen by two different methods
UNE-EN 13716:2002 Surface active agents - Determination of total base nitrogen - Potentiometric titration.
UNE-CEN/TS 15104:2008 EX Solid biofuels - Determination of total content of carbon, hydrogen and nitrogen - Instrumental methods

Korean Agency for Technology and Standards (KATS)

KS I ISO 11261-2008(2021) Soil quality－Determination of total nitrogen－Modified Kjeldahl method
KS I ISO 11261-2008(2018) Soil quality－Determination of total nitrogen－Modified Kjeldahl method
KS H ISO 1871-2013(2018) Agricultural food products ― General directions for the determination of nitrogen by the Kjeldahl method
KS I ISO 11261:2008 Soil quality-Determination of total nitrogen-Modified Kjeldahl method
KS M ISO 5315-2007(2012) Fertilizers－Determination of total nitrogen content－Titrimetric method after distillation
KS M ISO 6851-2002(2017) Photography－Processing waste－Determination of total amino nitrogen－Microdiffusion Kjeldahl method
KS M ISO 5315:2007 Fertilizers-Determination of total nitrogen content-Titrimetric method after distillation
KS M ISO 5315:2013 Fertilizers－Determination of total nitrogen content－Titrimetric method after distillation
KS M ISO 6851-2022 Photography－Processing waste－Determination of total amino nitrogen－Microdiffusion Kjeldahl method
KS M ISO 6851:2002 Photography-Processing waste-Determination of total amino nitrogen-Microdiffusion Kjeldahl method
KS D 2555-1995 Methods for determination of nitrogen in tantalum
KS D 2555-2015 Methods for determination of nitrogen in tantalum

Magyar Szabványügyi Testület

MNOSZ 448-27.lap-1955 Determination of total nitrogen water
MSZ 318/18-1981 Determination of total nitrogen in sludge test

German Institute for Standardization

DIN EN 15750:2010-02 Fertilizers - Determination of total nitrogen in fertilizers containing nitrogen only as nitric, ammoniacal and urea nitrogen by two different methods; German version EN 15750:2009
DIN EN 15750 E:2009 Draft Document - Fertilizers - Determination of total nitrogen in fertilizers containing nitrogen only as nitric, ammoniacal and urea nitrogen by two different methods; German version prEN 15750:2009
DIN CEN/TS 15750:2008 Fertilizers - Determination of total nitrogen in fertilizers containing nitrogen only as nitric, ammoniacal and urea nitrogen by two different methods; German version CEN/TS 15750:2008
DIN 51732 E:2013-07 Testing of solid mineral fuels - Determination of total carbon, hydrogen and nitrogen - Instrumental methods
DIN EN 15750 E:2009-04 Draft Document - Fertilizers - Determination of total nitrogen in fertilizers containing nitrogen only as nitric, ammoniacal and urea nitrogen by two different methods; German version prEN 15750:2009
DIN 51732:2007 Testing of solid mineral fuels - Determination of total carbon, hydrogen and nitrogen - Instrumental methods
DIN 51732:2014 Testing of solid mineral fuels - Determination of total carbon, hydrogen and nitrogen - Instrumental methods
DIN 51732:2014-07 Testing of solid mineral fuels - Determination of total carbon, hydrogen and nitrogen - Instrumental methods
DIN EN 13716:2003-05 Surface active agents - Determination of total base nitrogen - Potentiometric titration; German version EN 13716:2001
DIN CEN/TS 15104:2005 Solid biofuels - Determination of total content of carbon, hydrogen and nitrogen - Instrumental methods; German version CEN/TS 15104:2005
DIN EN 13716:2003 Surface active agents - Determination of total base nitrogen - Potentiometric titration; German version EN 13716:2001
DIN ISO 11261:1997 Soil quality - Determination of total nitrogen - Modified Kjeldahl method (ISO 11261:1995)

IN-BIS

IS 5194-1969 Determination method of nitrogen-Kjeldahl method
IS 3708 Pt.8-1986 Test methods for natural rubber latex Part 8 Determination of total nitrogen [NRL: 12]

PH-BPS

PTS 98-1970 Standardization of the Method of Test for the Determination of Total Nitrogen Content.Devarda Method

International Organization for Standardization (ISO)

ISO 11261:1995 Soil quality - Determination of total nitrogen - Modified Kjeldahl method
ISO 29541:2025 Coal and coke — Determination of total carbon, hydrogen and nitrogen — Instrumental method
ISO 5315:1984 Fertilizers; Determination of total nitrogen content; Titrimetric method after distillation
ISO 20620:2021 Fertilizers and soil conditioners - Determination of total nitrogen by combustion

Ente Nazionale Italiano di Unificazione

UNI EN 15750:2009 Fertilizers - Determination of total nitrogen in fertilizers containing nitrogen only as nitric, ammoniacal and urea nitrogen by two different methods
UNI CEN/TS 15478:2006 Fertilizers - Determination of total nitrogen in urea
UNI 9249:1988 Biomass. Determination of total nitrogen.
UNI 9971:1992 Adhesives. Determination of total nitrogen.
UNI EN 15561:2009 Fertilizers - Determination of total nitrogen in calcium cyanamide containing nitrates
UNI EN 12260:2004 Water quality - Determination of nitrogen - Determination of bound nitrogen (TNb), following oxidation to nitrogen oxides
UNI EN 15104:2011 Solid biofuels - Determination of total content of carbon, hydrogen and nitrogen - Instrumental methods
UNI CEN/TS 15104:2005 Solid biofuels - Determination of total content of carbon, hydrogen and nitrogen - Instrumental methods

YU-JUS

JUS H.B8.288-1983 Fertilizers. Determination of content total-nitrogen. Volumetric method
JUS H.G8.435-1990 Reaqents. Potassium iodide. Determination of total nitroaen content. Colorimetric method
JUS H.G8.083-1983 Reagents. Sodium chloride. Determination of total nitrogen content. Colorimetric method
JUS H.G8.457-1991 Reagents. Potassium sulpbate. Determination of total nltrogen content. Colorlmetrlc metho?
JUS H.G8.104-1984 Reagents. Potassium chloride. Determination of total nitrogen content. Colorimetric method
JUS H.G8.055-1983 Reagents. Hydrogen peroxide. Determination of total nitrogen content. Colorimetric method
JUS H.G8.415-1991 Reagents. So?ium hydroxide. Determination of total nitrogen content. Colorimetric method
JUS H.G8.290-1987 Reagents. Copper(ll) oxide. Determination of total nitrogen content. Colorimetric method
JUS H.G8.343-1988 Reagents. Zine chloride. Determination of total nitrogen content. Colorinetcic metbod

Lithuanian Standards Office

LST EN 15750-2010 Fertilizers - Determination of total nitrogen in fertilizers containing nitrogen only as nitric, ammoniacal and urea nitrogen by two different methods
LST EN 13716-2002 Surface active agents - Determination of total base nitrogen - Potentiometric titration

The Directorate General of Specifications and Metrology (DGSM)

OS GSO ISO 29441:2013 Water quality -- Determination of total nitrogen after UV digestion -- Method using flow analysis (CFA and FIA) and spectrometric detection

Association of German Mechanical Engineers

VDI 2456-2004 Measurement of gaseous emissions — Reference method for the determination of the sum of nitrogen monoxide and nitrogen dioxide — Ion chromatographic method
VDI 2456-2004 Measurement of gaseous emissions — Reference method for the determination of the sum of nitrogen monoxide and nitrogen dioxide — Ion chromatographic method
VDI 2456 Blatt 2-1973 Gaseous emission measurement; determination of the total sum of nitrogen monoxide and nitrogen dioxide; acidimetric titration method
VDI 2456-2003 Stationary source emissions - Determination of the total of nitrogen monoxide and nitrogen dioxide - Ion chromatography method

European Committee for Standardization (CEN)

PD CEN/TS 15750:2008 Fertilizers - Determination of different forms of nitrogen in fertilizers containing nitrogen only as nitric, ammoniacal and urea nitrogen by two different methods
EN 15750:2009 Fertilizers - Determination of total nitrogen in fertilizers containing nitrogen only as nitric, ammoniacal and urea nitrogen by two different methods
EN 13716:2001 Surface active agents - Determination of total base nitrogen - Potentiometric titration

GCC Standardization Organization

GSO ISO 29441:2013 Water quality -- Determination of total nitrogen after UV digestion -- Method using flow analysis (CFA and FIA) and spectrometric detection
GSO ISO 6851:2015 Photography -- Processing waste -- Determination of total amino nitrogen (microdiffusion Kjeldahl method)

Bureau of Indian Standards

IS 6092-2-5-2004 Methods of Sampling and Test for Fertilizers - Part 2 : Determination of Nitrogen - Section 5 : Total Nitrogen Content - Titrimetric Method after Distillation
IS 3025-34-4-2022 METHODS OF SAMPLING AND TEST PHYSICAL AND CHEMICAL FOR WATER AND WASTEWATER PART 34 NITROGEN Section 4 Determination of total nitrogen after UV digestion Method using flow analysis CFA and FIA and spectrometric detection

RO-ASRO

SR ISO 5315:1984 Fertilizers. Determination of totai nitrogen content.Titrimetric method after distilation

SE-SIS

SIS SS 02 81 86-1985 Determination of total arsenic in water - Silver diethyldithiocarbamate spectrometric method

SCC

SPC GB/T 24583.7-2019 Vanadium-nitrogen -- Determination of oxygen content -- Infrared absorption method (TEXT OF DOCUMENT IS IN CHINESE)
SPC GB/T 24583.4-2019 Vanadium-nitrogen -- Determination of carbon content -- Infrared absorption method (TEXT OF DOCUMENT IS IN CHINESE)

Japanese Industrial Standards Committee (JISC)

JIS H 1685:2000 Method for determination of nitrogen in tantalum

CEN - European Committee for Standardization

PD CEN/TS 15478:2006 Fertilizers - Determination of total nitrogen in urea