Fur — Chemical Tests — Determination of pH
1 Scope
This standard specifies a method for determining the pH value and the difference of pH value between original aqueous solution and diluted solution of an aqueous fur extract.
This standard is applicable to all types of furs.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 6682 Water for Analytical Laboratory Use — Specification and Test Methods (GB/T 6682-2008, ISO 3696:1987, MOD)
QB/T 1266 Fur — Physical and Mechanical Tests — Sample Preparation and Conditioning (ISO 2419)
QB/T 1267 Fur — Chemical, Physical and Mechanical and Fastness Tests — Sampling Location (ISO 2418)
QB/T 1272-2012 Fur — Preparation of Chemical Test Samples (ISO 4044)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
difference of pH value between original aqueous solution and diluted solution
difference of pH value between original aqueous solution and solution diluted 10 times
Note: The difference figure is a measure of the strength of acids and bases and can never exceed a value of 1. The difference figure amounts to 0.7 to 1.0 when a solution contains a free strong acid (or a free strong base). The ionization of weak acids and bases increases with greater dilution, and therefore the difference figure can only act as a criterion for the presence of free strong acid or base in aqueous extracts with pH values below 4.0 or above 10.0.
4 Principle
Preparation of an aqueous extract from a test portion of the fur and measurement of the pH of the extract, using a pH meter. In cases where the pH value obtained is below 4.0 or above 10.0, the difference of pH value between original aqueous solution and diluted solution shall be determined.
Foreword II
1 Scope
2 Normative References
3 Terms and definitions
4 Principle
5 Reagents
6 Apparatuses
7 Sampling and Preparation of Samples
8 Procedure
9 Expression of Results
10 Reproducibility
11 Test Report
