SIST ISO 5397:1998 PDF

Name: SIST ISO 5397:1998 — Leather -- Determination of nitrogen content and "hide substance" -- Titrimetric method
SKU: SIST ISO 5397:1998
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Leather -- Determination of nitrogen content and "hide substance" -- Titrimetric method

Название (английский):

SIST ISO 5397:1998

Leather -- Determination of nitrogen content and "hide substance" -- Titrimetric method

Статус документа:: Действующий
Формат:: Электронный (PDF)
Количество страниц:: 3
Дата публикации:: 1 апреля 1998 г.
ICS:: 59.140.30
Технический комитет:: IUSN - Leather

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Описание (английский):

The principle consists in decomposition of a test portion by Kjeldahl method, distillation of the ammonia liberated, determination of the nitrogen content by titration of the ammonia with sulfuric or hydrochloric acid, using phenolphthalein as indicator. The method is applicable to all types of leather in all types of tannage.

Abstract

Похожие стандарты

Стандарты, упомянутые в описании

Overview

ISO 5397:1984 - Leather - Determination of nitrogen content and “hide substance” - Titrimetric method - specifies a Kjeldahl-based titrimetric procedure for measuring nitrogen content and calculating hide substance in leather. The method covers decomposition of a test portion by Kjeldahl digestion, steam distillation of liberated ammonia, and titration of the ammonia with standardized sulfuric or hydrochloric acid using phenolphthalein. It is applicable to all types of leather and all types of tannage.

Key topics and requirements

Principle: Kjeldahl digestion → distillation of ammonia → titration (titrimetric method).

Test portions: typically 3 g ground leather (2 g for chrome leather); optional micro-scale procedure noted.

Reagents: fuming or concentrated sulfuric acid, catalyst mixtures (examples: CuSO4 + K2SO4 or Se + CuSO4 + K2SO4), boric acid receiver solution with mixed indicator, 35% NaOH, standardized H2SO4 or HCl (0.5 mol/L), phenolphthalein.

Apparatus: Kjeldahl flask, distillation apparatus, burette compliant with ISO 385.

Calculation:

Nitrogen content N (%) = (V × 0.7) / m where V = titrant volume (mL) corrected for blank, m = mass of test portion (g).
Hide substance H (%) = N × 5.62

Quality and repeatability:

Duplicate determinations required; mean reported to one decimal place if repeatability met.
Duplicate results by same operator in same lab shall not differ by more than 0.1% (absolute, original mass basis).

Interferences: presence of other nitrogenous substances (certain fixatives, synthetic tannins, cationic fats, dyestuffs) can falsify hide substance values; not possible to obtain accurate hide substance where such materials are present.

Endpoint: titrate to pH ~4.6 (or first permanent pale pink with the specified indicator).

Applications and users

ISO 5397 is primarily used for:

Leather testing laboratories and quality control in tanneries.

Leather technologists, chemists, and research institutions evaluating nitrogen content and protein-derived hide substance in pelts and finished leather.

Manufacturers and regulatory bodies requiring standardized, comparable measurements across products and batches. Practical uses include process control, raw material evaluation, specification compliance, and comparative analyses of tanning effects on leather protein content.

Related standards

ISO 385 - Laboratory glassware - Burettes

ISO 2418 - Leather - Laboratory samples - Location and identification

ISO 2588 - Leather - Sampling - Number of items for a gross sample

ISO 4044 - Leather - Preparation of chemical test samples

Keywords: ISO 5397, leather testing, Kjeldahl method, titrimetric method, nitrogen content, hide substance, tanning, leather laboratory.

SIST ISO 5397:1998 PDF

Abstract

Похожие стандарты

Overview

Key topics and requirements

Applications and users

Related standards

Технические детали

ISO 5397:1984

Leather — Determination of nitrogen content and "hide substance" — Titrimetric method

BS EN ISO 385:2005

Laboratory glassware. Burettes.

BS EN ISO 24181-1:2025

Rare earth. Determination of non-rare earth impurities in individual rare earth metals and their oxides. ICP-…

SIST EN ISO 2588:2014

Leather - Sampling - Number of items for a gross sample (ISO 2588:2014)

SIST EN ISO 4044:2017

Leather - Chemical tests - Preparation of chemical test samples (ISO 4044:2017)