GB/T 23948-2023 in English

Introduction and background

GB/T 23948-2023 "General method for determination of water-insoluble matter in inorganic chemical products" is revised on the basis of the original standard GB/T 23948-2009, which mainly puts forward new requirements and improvements for the determination of water-insoluble matter in inorganic chemical products. The release of the new standard marks that the technical specifications and test methods in this field have been further improved.

The main changes in this standard include the expansion of the scope of application, the addition of sample weighing regulations, and the adjustment of the application scope and technical details of three different determination methods (glass sand crucible method, Gooch crucible method, microporous membrane method). In addition, the mass constant operation steps are introduced to ensure the accuracy and reliability of the determination results.

Scope of application of the standard

This standard applies to the determination of water-insoluble matter in inorganic chemical products. The specific method to be selected depends on the nature of the product:

• Glass sand crucible method: Applicable to non-alkaline products.
• Gooch crucible method: Applicable to all types of products.
• Microporous membrane method (made of polytetrafluoroethylene): Applicable to aqueous solution products with a pH value in the range of 2 to 13.

Comparison of experimental steps and methods

Mass constant operation steps

Mass constant operation is an important link to ensure the accuracy of the measurement results. The specific steps are as follows:

1. The first drying time is 1 hour to 2 hours.
2. Weigh after cooling in a dryer for 30 minutes.
3. Dry again for 30 minutes, and repeat the above steps until the mass difference between two consecutive weighings does not exceed 0.0002 grams.

Test Data Processing and Result Analysis

The water-insoluble content is expressed as mass fraction $$w and is calculated according to formula (1):

w = [(m₂ - m₁) / m] × 100%

• m₂: water-insoluble matter and filtration equipment mass, in grams (g).
• m₁: filtration equipment mass, in grams (g).
• m: sample mass, in grams (g).

The absolute difference between the two parallel determination results shall comply with the provisions of the product standard. The arithmetic mean of the parallel determination results shall be taken as the final determination result.

Implementation Suggestions

To ensure the effective implementation of GB/T 23948-2023 standard, it is recommended that enterprises:

• Choose appropriate measurement methods according to the properties of the product.
• Regularly calibrate instruments and equipment to ensure that the accuracy meets the requirements.
• Strengthen personnel training and master new measurement techniques and operating specifications.
• Refer to the qualitative test method in Appendix A to further verify the filtrate composition and improve the accuracy of the test.