EN 25663:1993
(Main)Water quality - Determination of Kjeldahl nitrogen - Method after mineralization with selenium (ISO 5663:1984)
Water quality - Determination of Kjeldahl nitrogen - Method after mineralization with selenium (ISO 5663:1984)
Specifies a procedure for the determination of trivalent negative nitrogen. Organic nitrogen in the form of azide, azine, azo, hydrazone, nitrite, nitro, nitroso, oxime or semicarbazone is not determined quantitatively. The procedure is applicable to the analysis of raw, potable and waste waters.
Wasserbeschaffenheit - Bestimmung von Kjeldahl-Stickstoff - Verfahren nach Aufschluß mit Selen (ISO 5663:1984)
Qualité de l'eau - Dosage de l'azote Kjeldahl - Méthode après minéralisation au sélénium (ISO 5663:1984)
1.1 Substance dosée La présente Norme internationale spécifie une méthode de dosage de l'azote par une méthode de type Kjeldahl. Seul l'azote à l'état trivalent négatif est dosé. L'azote organique du type azide, azine, azoïque, hydrazone, nitrite, nitré, nitrosé, oxime ou semicarbazone n'est pas dosé quantitativement. L'azote des composés hétérocycles peut être incomplètement récupéré. 1.2 Type d'échantillon La présente méthode est applicable aux eaux brutes, aux eaux potables et aux eaux résiduaires. 1.3 Étendue du dosage Une teneur en azote Kjeldahl, ρN jusqu'à 10 mg dans la prise d'essai peut être déterminée. Avec une prise d'essai de 10 ml, cela correspond à une concentration d'azote dans l'échantillon de ρN = 1 000 mg/l. 1.4 Limite de détection La limite de détection, déterminée expérimentalement (4 degrés de liberté), avec une prise d'essai de 100 ml est ρN = 1 mg/l. 1.5 Sensibilité Avec une
Kakovost vode - Določanje dušika po Kjeldahlu - Metoda po mineralizaciji s selenom (ISO 5663:1984)
General Information
- Status
- Published
- Publication Date
- 29-Sep-1993
- Withdrawal Date
- 30-Mar-1994
- Technical Committee
- CEN/TC 230 - Water analysis
- Drafting Committee
- CEN/TC 230 - Water analysis
- Current Stage
- 9093 - Decision to confirm - Review Enquiry
- Start Date
- 21-May-2008
- Completion Date
- 21-May-2008
Relations
- Referred By
EN 500-1:2006+A1:2009 - Mobile road construction machinery - Safety - Part 1: Common requirements - Effective Date
- 28-Jan-2026
Overview
EN 25663:1993 (equivalent to ISO 5663:1984) specifies a laboratory procedure for the determination of Kjeldahl nitrogen after mineralization with selenium. The method is designed to quantify trivalent (Kjeldahl) nitrogen in a variety of water matrices, including raw, potable and waste waters. It is a standardized approach published by CEN to support consistent water quality assessment and laboratory analysis.
This standard clarifies the scope and limitations of the selenium-mineralization Kjeldahl technique. Notably, certain organic nitrogen forms - such as azide, azine, azo, hydrazone, nitrite, nitro, nitroso, oxime and semicarbazone - are not determined quantitatively by this procedure.
Key Topics
- Scope and applicability: Procedure applicable to raw, drinking (potable) and wastewater samples for the determination of trivalent nitrogen.
- Mineralization approach: Uses selenium-assisted mineralization prior to Kjeldahl nitrogen determination (as per ISO 5663:1984 equivalence).
- Limitations: Explicitly excludes quantitative determination of specific organic nitrogen derivatives (listed in the standard).
- Standardization and provenance: Adopted by CEN and aligned with ISO 5663:1984; intended for routine analytical use in accredited laboratories.
Applications
The EN 25663:1993 method provides practical value across laboratory and environmental monitoring contexts:
- Routine water quality monitoring: Suitable for municipal and industrial laboratories assessing nitrogen load in influent and effluent streams.
- Potable water analysis: Supports evaluation of nitrogen species that affect drinking water treatment and compliance checks.
- Wastewater treatment control: Helps monitor organic and ammoniacal nitrogen transformations where Kjeldahl nitrogen is a relevant parameter.
- Regulatory and reporting: Provides a standardized basis for reporting trivalent nitrogen results in conformity with regional or national requirements.
Benefits include repeatability when performed under controlled laboratory conditions, alignment with international practice (ISO), and clear scope statements that guide interpretation of results.
Related Standards
- ISO 5663:1984 - Original international method for Kjeldahl nitrogen determination after selenium mineralization (EN 25663:1993 is equivalent).
- Other related water-quality and nitrogen-analysis standards address alternative digestion reagents, total nitrogen methods, or methods for specific nitrogen species (consult local regulatory frameworks for applicable complementary standards).
For laboratories implementing EN 25663:1993, ensure personnel are trained in Kjeldahl procedures and that method limitations (excluded organic nitrogen forms) are considered when interpreting results for regulatory or research purposes.
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Frequently Asked Questions
EN 25663:1993 is a standard published by the European Committee for Standardization (CEN). Its full title is "Water quality - Determination of Kjeldahl nitrogen - Method after mineralization with selenium (ISO 5663:1984)". This standard covers: Specifies a procedure for the determination of trivalent negative nitrogen. Organic nitrogen in the form of azide, azine, azo, hydrazone, nitrite, nitro, nitroso, oxime or semicarbazone is not determined quantitatively. The procedure is applicable to the analysis of raw, potable and waste waters.
Specifies a procedure for the determination of trivalent negative nitrogen. Organic nitrogen in the form of azide, azine, azo, hydrazone, nitrite, nitro, nitroso, oxime or semicarbazone is not determined quantitatively. The procedure is applicable to the analysis of raw, potable and waste waters.
EN 25663:1993 is classified under the following ICS (International Classification for Standards) categories: 13.060.30 - Sewage water. The ICS classification helps identify the subject area and facilitates finding related standards.
EN 25663:1993 has the following relationships with other standards: It is inter standard links to EN 500-1:2006+A1:2009. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
EN 25663:1993 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Wasserbeschaffenheit - Bestimmung von Kjeldahl-Stickstoff - Verfahren nach Aufschluß mit Selen (ISO 5663:1984)Qualité de l'eau - Dosage de l'azote Kjeldahl - Méthode apres minéralisation au sélénium (ISO 5663:1984)Water quality - Determination of Kjeldahl nitrogen - Method after mineralization wi
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