SIST EN ISO 3188:1998 PDF
Starches and derived products - Determination of nitrogen content by the Kjeldahl method - Titrimetric method (ISO 3188:1978)
Starches and derived products - Determination of nitrogen content by the Kjeldahl method - Titrimetric method (ISO 3188:1978)
- Статус документа:
- Действующий
- Формат:
- Электронный (PDF)
- Количество страниц:
- 5
- Дата публикации:
- 1 ноября 1998 г.
- ICS:
- 67.180.20
- Технический комитет:
- KŽP - Agricultural food products
The found value only includes free amino acids, compounds producing amino acids on hydrolysis and ammonium compounds. The principle consists in destruction of organic matter by sulphuric acid in the presence of a compound catalyst (see ISO 1871), alkalization of the reaction products, distillation of the liberated ammonia and collection in a boric acid solution, followed by titration with a standard volumetric sulphuric acid solution. The method applies to contents greater than 0,01 % (m/m). For products with contents less than 0,025 % (m/m), see ISO 5378.
Abstract
Overview
EN ISO 3188:1994 (ISO 3188:1978) specifies a titrimetric Kjeldahl method for determining the nitrogen content of starches and derived products. The method is intended for materials with a presumed nitrogen content greater than 0.01% (m/m). It covers destruction of organic matter by sulphuric acid with a compound catalyst, alkalization, distillation of liberated ammonia into boric acid and titration with a standard volumetric sulphuric acid solution. Results include free amino acids, compounds yielding amino acids on hydrolysis and ammonium compounds; nitrate/nitrite and nitrogen bound to oxygen or directly to another nitrogen atom are excluded.
Key topics and technical requirements
- Scope and applicability
- For starches and derivatives with nitrogen > 0.01% (m/m). For very low levels (
Технические детали
- SKU
- SIST EN ISO 3188:1998
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