ASTM D7785-12
Standard Test Method for Water in Lint Cotton by Oven Evaporation Combined with Volumetric Karl Fischer Titration
- Standard No.
- ASTM D7785-12
- Release Date
- 2012
- Published By
- American Society for Testing and Materials (ASTM)
- Status
- Replace By
- ASTM D7785-21
- Latest
- ASTM D7785-21
- Scope
The water content of raw or lint cotton determined by this test method, calculated from the required volume of reagent, may be greater, equal to or less than the moisture content measured by standard oven drying methods. These differences may be of significance in commercial transactions (1-3) (see also Appendix X2). Water content by this method is not to be considered the same attribute as moisture content.
Standard test methods using volumetric and coulometric Karl Fischer reagent are two of the most widely used procedures for the determination of water.
The volumetric method is typically used for the routine determination of water in the mass percent range of concentrations. If samples contain very low levels of water, the coulometric technique should be considered (see Test Methods D1533, E1064).
This test method for testing the water content of cotton can be used for acceptance testing of commercial shipments of lint cotton, manufacturing control and calibration of fast, indirect sensors to measure water.
Information on the water content of cotton is desirable since the physical properties of cotton are significantly affected by its water content. Variations in the amount of water present, or its regain, affect the mass and hence the market value of a lot of material.
The observed volume of Karl Fischer reagent used in this test method to analyze a specimen represents the water in the absence of side reactions in an oven supplied with air (3).
Note 28212;Side reactions in cotton that confound the actual weight loss due to water have been demonstrated in two laboratory ovens and a thermogravimetric analysis oven supplied with air (3). This results in an approximation regarding the actual amount of water in cotton based on mass loss by drying. If the moisture content by oven drying agrees with the water content measured by Karl Fischer titration, the one-to-one correspondence may be coincidental due to the presence of both negative and positive biases in moisture content values.
1.1 This test method covers the determination of the total amount of water (free and bound) in raw and lint cotton at moisture equilibrium from conditioning in the standard atmosphere for testing textiles.
Note 18212;For other methods of determination of moisture in lint cotton that do not specify conditioning to moisture equilibrium, refer to Test Methods D2495 and D1348.
1.2 This test method requires the use of oven evaporation to remove all of the water in the fiber matrix, volumetric Karl Fischer (KF) titration to determine water content and water regain, and control current potentiometry to detect the end point.
1.3 This test method is not intended for use with potentiometric (zero current) and coulometric Karl Fischer titrators (see Test Methods D1533, D4377 and E1064), nor is this test method intended to be used with methanol extracts of cotton (See Test Methods D1348).
1.4 The values stated in SI units are to be regarde......
ASTM D7785-12 Referenced Document
- ASTM D1193 Standard Specification for Reagent Water
- ASTM D123 Standard Terminology Relating to Textiles
- ASTM D1348 Standard Test Methods for Moisture in Cellulose
- ASTM D1441 Standard Practice for Sampling Cotton Fibers for Testing
- ASTM D1533 Standard Test Method for Water in Insulating Liquids by Coulometric Karl Fischer Titration*， 2024-04-19 Update
- ASTM D1776 Standard Practice for Conditioning and Testing Textiles
- ASTM D2495 Standard Test Method for Moisture in Cotton by Oven-Drying
- ASTM D4377 Standard Test Method for Water in Crude Oils by Potentiometric Karl Fischer Titration
- ASTM D7139 Standard Terminology for Cotton Fibers
- ASTM E1064 Standard Test Method for Water in Organic Liquids by Coulometric Karl Fischer Titration
- ASTM E177 Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
- ASTM E203 Standard Test Method for Water Using Volumetric Karl Fischer Titration
- ASTM E691 Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
ASTM D7785-12 history
- 2021 ASTM D7785-21 Standard Practice for Water in Lint Cotton by Oven Evaporation Combined with Volumetric Karl Fischer Titration
- 2012 ASTM D7785-12 Standard Test Method for Water in Lint Cotton by Oven Evaporation Combined with Volumetric Karl Fischer Titration
