ISO 8112:2023

Caprolactam for industrial use - Determination of colour of 50 % aqueous caprolactam solution, expressed in Hazen units (platinum-cobalt scale) - Spectrometric method

This document specifies a spectrometric method of determining the colour, expressed in Hazen units, of a 50 % aqueous caprolactam solution as a measure of coloured impurities content of the sample.

Caprolactame à usage industriel — Détermination de la coloration d'une solution aqueuse à 50 % de caprolactame, exprimée en unités Hazen (échelle platine-cobalt) — Méthode spectrométrique

General Information

• Status: Published
• Publication Date: 16-Jul-2023
• ICS: 71.080.30 - Organic nitrogen compounds
• Technical Committee: ISO/TC 61/SC 5 - Physical-chemical properties
• Drafting Committee: ISO/TC 61/SC 5 - Physical-chemical properties
• Current Stage: 6060 - International Standard published
• Start Date: 17-Jul-2023
• Due Date: 22-Sep-2024
• Completion Date: 17-Jul-2023

Relations

• Revises: ISO 8112:1984 - Caprolactam for industrial use - Determination of colour of 50 % aqueous caprolactam solution, expressed in Hazen units (platinum-cobalt scale) - Spectrometric method
• Effective Date: 06-Jun-2022

Overview

ISO 8112:2023 specifies a precise spectrometric method for determining the colour of a 50% aqueous caprolactam solution, expressed in Hazen units on the platinum-cobalt (Pt/Co) scale. This international standard is essential for assessing the coloured impurities content in industrial-grade caprolactam. By measuring absorbance at a wavelength of 390 nm, it ensures consistent and objective colour evaluation to support quality control and product standardization in caprolactam production.

Key Topics

• Scope: Defines a standardized approach to measure colour intensity in 50% aqueous caprolactam solutions using spectrometry.
• Principle: Measures absorbance at 390 nm with an optical path length of 50 mm. The absorbance is converted to Hazen units using a factor of 150, derived from the platinum-cobalt scale.
• Reagents and Equipment: Requires distilled or equivalent purity water, standard laboratory apparatus, and a spectrometer capable of 390 nm measurements.
• Procedure:
  • Preparation of a 50% caprolactam solution.
  • Baseline measurement using water-filled cells.
  • Measurement of caprolactam solution’s absorbance.
  • Option to use flow-through cells for continuous measurement.
• Expression of Results: Results rounded to the nearest whole Hazen unit. The method accounts for different optical path lengths by adjusting the calculation factor accordingly.
• Reporting Requirements: Test reports must include sample identification, method references, results, instrumentation details, and any deviations or noteworthy observations.

Applications

ISO 8112:2023 is crucial for industries involved in producing or utilizing industrial-grade caprolactam, especially where colour purity impacts downstream processing or product quality. Applications include:

• Quality control laboratories testing caprolactam batches to ensure conformance with purity and colour specifications.
• Chemical manufacturing plants monitoring caprolactam impurities to optimize production processes.
• Polyamide production where the colour of caprolactam influences the aesthetics and performance of nylon polymers.
• Supply chain verification for raw material acceptance in industrial environments.

By adopting this spectrometric method, organizations benefit from an objective, reproducible, and internationally recognized procedure for colour determination, improving transparency and consistency in material quality assessment.

Related Standards

• ISO 2211: Liquid chemical products - Measurement of colour in Hazen units (platinum-cobalt scale)
  This standard provides foundational methods for colour measurement in liquids using the platinum-cobalt scale, which ISO 8112:2023 references for calibration and standardization.

• ISO/IEC Directives, Part 1 and Part 2
  Governs the editorial principles and procedural rules for development and maintenance of ISO documents, ensuring clarity and uniformity across standards.

• Other ISO standards on plastics and chemical testing published by ISO/TC 61 related to physical-chemical properties may complement ISO 8112 for comprehensive quality control.

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Keywords: ISO 8112:2023, caprolactam colour determination, Hazen units, platinum-cobalt scale, spectrometric method, industrial caprolactam, colour impurities, 50% aqueous caprolactam, spectrometer, quality control, chemical industry standards.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 8112
Second edition
2023-07
Caprolactam for industrial use —
Determination of colour of 50 %
aqueous caprolactam solution,
expressed in Hazen units (platinum-
cobalt scale) — Spectrometric method
Caprolactame à usage industriel — Détermination de la coloration
d'une solution aqueuse à 50 % de caprolactame, exprimée en unités
Hazen (échelle platine-cobalt) — Méthode spectrométrique
Reference number
© ISO 2023
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Published in Switzerland
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reagents . 1
6 Apparatus . 1
7 Procedure .2
8 Expression of results . 2
9 Test report . 3
iii
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This document was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 5, Physical-
chemical properties.
This second edition cancels and replaces the first edition (ISO 8112:1984), which has been technically
revised.
The main changes are as follows:
— the option to use a flow-through cell for the absorption measurement has been added;
— the temperature of measured solution has been taken into account.
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