ISO 7408-1983 PDF
Name in English:
St ISO 7408-1983
Name in Russian:
Ст ISO 7408-1983
Original standard ISO 7408-1983 in PDF full version. Additional info + preview on request
Full title and description
St ISO 7408-1983 — Fertilizers — Determination of ammoniacal nitrogen content in the presence of other substances which release ammonia when treated with sodium hydroxide — Titrimetric method. This International Standard specifies a titrimetric procedure for measuring ammoniacal nitrogen in fertilizer samples where other substances may release ammonia on treatment with sodium hydroxide.
Abstract
The method consists of entraining, by means of a strong current of air, the ammonia from a moderately alkaline test mixture at ambient temperature into a standard volumetric sulfuric acid solution, followed by back‑titration of the excess sulfuric acid with standard volumetric sodium hydroxide solution. The procedure is intended for use with fertilizer materials in which interfering substances may release ammonia when treated with NaOH.
General information
- Status: Published (confirmed on review; current edition remains in force).
- Publication date: December 1983 (1983-12).
- Publisher: International Organization for Standardization (ISO).
- ICS / categories: 65.080 (Fertilizers).
- Edition / version: Edition 1 (1983).
- Number of pages: 5.
Key bibliographic and life‑cycle details above are recorded in the ISO catalogue entry for ISO 7408:1983, which shows the document as published by ISO/TC 134 and confirmed on periodic review.
Scope
Specifies a titrimetric method for determination of ammoniacal nitrogen in fertilizers when other substances present in the sample may release ammonia upon treatment with sodium hydroxide. The standard describes sample treatment to create a moderately alkaline mixture, aeration (entrainment of evolved ammonia into standardized sulfuric acid), and back‑titration of excess acid with sodium hydroxide — providing a quantitative result for ammoniacal nitrogen in such matrices.
Key topics and requirements
- Preparation of a moderately alkaline test mixture (sample + NaOH) to release ammonia from ammoniacal forms and from substances that liberate ammonia on alkalization.
- Entraining evolved ammonia by a strong current of air into a standard volumetric sulfuric acid solution (aeration/absorption step).
- Back‑titration of excess sulfuric acid with standard volumetric sodium hydroxide to quantify captured ammonia.
- Instructions for reagents, standard solutions and titrimetric technique appropriate for fertilizer matrices.
- Applicability notes and procedural limits for interference control in complex fertilizer samples.
Typical use and users
Analytical and quality‑control laboratories in fertilizer manufacturing and testing, regulatory and inspection bodies assessing fertilizer composition, research laboratories working on fertilizer composition and behavior, and national standards/adoption bodies. The method is intended for routine determination of ammoniacal nitrogen where interfering ammonia‑releasing substances are present.
Related standards
ISO 7408:1983 is published under the work of ISO/TC 134 (Fertilizers, soil conditioners and beneficial substances) and sits alongside other fertilizer standards and sampling/test methods. Relevant related documents and nearby ISO items include other ISO/TC 134 standards such as ISO 7409 (marking and declarations for fertilizers) and ISO 7410 (final samples — practical arrangements), and sampling/test standards like ISO 8634 (sampling plans for solid fertilizers). National adoptions and identical/adapted equivalents exist in some countries.
Keywords
ammoniacal nitrogen, fertilizers, titrimetric method, aeration, sodium hydroxide, sulfuric acid, ISO 7408, ISO/TC 134, fertilizer analysis, interference control.
FAQ
Q: What is this standard?
A: ISO 7408:1983 is an International Standard that defines a titrimetric method for determining ammoniacal nitrogen in fertilizer samples where other substances may liberate ammonia on treatment with sodium hydroxide.
Q: What does it cover?
A: It covers the procedural steps for making the test mixture alkaline, entraining the released ammonia into standardized sulfuric acid by a strong current of air, and back‑titrating the excess acid with standardized sodium hydroxide to determine the ammoniacal nitrogen content.
Q: Who typically uses it?
A: Fertilizer producers' QC labs, independent testing laboratories, regulatory authorities and research groups concerned with fertilizer composition and compliance.
Q: Is it current or superseded?
A: The ISO catalogue indicates ISO 7408:1983 was reviewed and confirmed (most recently recorded in ISO’s review history), and the 1983 edition remains the published version in the ISO catalogue (confirmed on periodic review). Users should check national adoption or replacement notices for any country‑specific withdrawals or supersessions before application.
Q: Is it part of a series?
A: It is part of the body of fertilizer standards maintained by ISO/TC 134 (Fertilizers, soil conditioners and beneficial substances). It is one of several ISO methods and guidance documents addressing sampling, analysis and labelling for fertilizers.
Q: What are the key keywords?
A: Ammoniacal nitrogen; fertilizers; titrimetric; aeration/entrainment; sodium hydroxide; sulfuric acid; ISO 7408; fertilizer analysis.