Standard Practice for Water in Lint Cotton by Oven Evaporation Combined with Volumetric Karl Fischer TitrationName übersetzen
NORM herausgegeben am 1.1.2021
Bezeichnung normen: ASTM D7785-21
Ausgabedatum normen: 1.1.2021
Zahl der Seiten: 7
Gewicht ca.: 21 g (0.05 Pfund)
Land: Amerikanische technische Norm
Kategorie: Technische Normen ASTM
Karl Fischer reagent, lint cotton, pyridine-free, volumetric Karl Fischer titration, water content, water regain,, ICS Number Code 59.080.01 (Textiles in general)
|Significance and Use|
5.1The water content of raw or lint cotton determined by this practice, 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 (5.2Standard test methods using volumetric and coulometric Karl Fischer reagent are two of the most widely used procedures for the determination of water.
5.3The 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 , ).
5.4This practice 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.
5.5Information 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.
5.6The observed volume of Karl Fischer reagent used in this practice to analyze a specimen represents the water in the absence of side reactions in an oven supplied with air ().
Note 2: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 (1.1This practice 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 1:For other methods of determination of moisture in lint cotton that do not specify conditioning to moisture equilibrium, refer to Test Methods and .
1.2This practice 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.
1.3This practice is not intended for use with potentiometric (zero current) and coulometric Karl Fischer titrators (see Test Methods , and ), nor is this practice intended to be used with methanol extracts of cotton (See Test Methods ).
1.4The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.6This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
|2. Referenced Documents|
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