Determination of water content

The complete analysis of alcohol sulfates is described in the Standard Methods of the International Organization of Standards (ISO) [200] and of the American Society for Testing and Materials (ASTM) [201]. These methods describe the analysis of inorganic sulfate content, chloride content, unsulfated matter, and water as well as other analytical values. Other ISO standards describe the analysis of sodium secondary alkyl sulfates [202], determination of pH [203], determination of water content [204,205], chlorides [206], total active matter in sul fated ethoxylated alcohols and alkylphenols [207], mean relative molecular mass in sulfated ethoxylated alcohols and alkylphenols [208], sulfate content... 

ISO 4317 1991, Surface active agents and detergents Determination of water content—Karl Fischer method. 

ISO 4318 1989, Surface active agents and soaps Determination of water content—Azeotropic distillation method. 

Soil is hygroscopic. The water content of air dry soil will increase and decrease as the relative humidity of the air it is exposed to changes. The uptake of water by oven dry soil is shown in Figure 7.10. Thus, determination of water content just before analysis is critical. 

It refers to the determination of water content titrimetrically with Karl Fischer Reagent (KFR). This technique has been used exclusively for the determination of water content in a number of pharmaceutical substances listed below (see Part II G, Chapter 14) ... 

Thomas R. (2000) Determination of water contents of granite melt inclusions by confocal laser Raman microprobe spectroscopy. Am. Mineral. 85, 868-872. 

Ohta, S., M. Hori, S. Yamagata, and N. Murao, Chemical Characterization of Atmospheric Fine Particles in Sapporo with Determination of Water Content, Atmos. Environ., 32, 1021-1025 (1998). 

Additional reagents and equipment for gravimetric determination of water content by drying (unitai.i) or Karl Fischer titration (unitai.2)... 

The infrared moisture analyser may also be used for quick determination of water content although it gives a value that is different than the other two methods (subject of a future unit on NIR). This may be useful if a rapid IR method is used in a production line so one can correlate line moisture with true moisture. 

Tran, C. D. and Grishko, V. I. (2004) Determination of water contents in leaves by a near-infrared multispectral imaging technique. Microchem. J. 76, 91-94. 

Karl Fischer electrometric titration method for determination of water content (WHO/M/7.R1)... 

Results from weight-loss measurements were modeled.f Research indicates that the determination of water content by Karl Fischer analysis in effervescent tablets was possible after extraction with diox-ane. NaHCOs, which reacts with the Karl Fischer reagent, is insoluble in dioxane and does not interfere during the determination. 

Materials Determination of Water Content of Polyols, 4 pp (Comm D-20)... 

J. M. Zink, J. L. Koenig, and T. R. Williams, Determination of Water Content in Bovine Lenses Using Near-Infrared Spectroscopy, Ophthalmic Res., 29(6), 429-435 (1997). 

The second example illustrates the determination of water content which is an important characteristic for chemical substances and is needed in many chemical reactions. It is usually determined by Karl-Fischers (KF) titration. The water content determined in our laboratory ranges from <0.1% to about 30%. It is widely known that KF water titration s may be influenced by the sample and, depending on the range, some other parameters may significantly affect the uncertainty. 

Essential oils - Determination of water content - Karl Fischer method... 

IDF Standard. Dried milk and dried cream. Determination of Water Content, 26A, 1993. 

Measurement of moisture uptake is typically done by either of two general methods. The classical approach involves equilibration of solid at several different humidities and the subsequent determination of water content either by gravimetric or analytical methods such as Karl Fischer titration or loss on drying. Moisture adsorption or desorption may be measured by use of this method and the pro-... 

ASTM D4672, Standard Test Methods for Polyurethanes Raw Materials Determination of Water Content in Polyols, 2000. 

ISO 14897, Plastics - Polyols for use in the Production of Polyurethane -Determination of Water Content, 2002. 

TABLE 14.8 Determination of water content in various commercial ATH samples from their ashing (at 525°C for 24 h) data. The manufacturers names are listed on p. 474. 

This study illustrated a drawback to using IR for quantitative analyses because you must rely upon an independent assay for the calibration. The limited number of runs conducted did, however, demonstrate feasibility of online determination of water content. From a manufacturing perspective, this technology would greatly reduce the cycle time for the process by eliminating the need to suspend the vacuum concentration used to azeotropically remove water in order to obtain a sample for off-line analysis. 

Of particular interest for the determination of water content is the use of a liquid reagent such as 2,2-dimethoxypropane, which yields liquid products (acetone and methanol) during hydrolysis [79—81]. To accelerate the hydrolysis it is conducted on a water-bath with heating in the presence of methylsulphuric acid (catalyst). The hydrolysis lasts 1 min. The method was applied to the determination of water in organic solvents and crystal hydrates of salts. 

G.F. Nichugovsky, Opredelnie Vlazhnosti Khimicheskikh Veshchestv (Determination of Water Content in Chemical Substances), Khimiya, Leningrad, 1977. 

Experiment 21. Study of some important parameters in GC Experiment 22. The determination of some chlorinated insecticides by capillary GC using an EC detector Experiment 23. Analysis of paint shop vapours Experiment 24. The determination of water content in solvents by capillary and packed GC using thermal conductivity detection Experiment 25. Analysis of mineral acids as their cyclohexyl derivatives by capillary GC and GC-MS... 

Determination of water content in solvents by capillary and packed GC using thermal conductivity detection. 

Part 5 Determination of water content by drying in a ventilated oven... 

The analysis of water content in foods is one of the most frequently and routinely performed analyses of foods. Methods used in the analysis of water are outlined in Figure 1.1. The great variability in water contents of food materials requires that the results of other analyses of foods are to be reported on a dry weight basis. This is one of the main reasons for the routine determination of water content in the food laboratory. While there is ongoing research to achieve improvements in the methods of water analysis [19,20], recent interest is also forwarded to the economic aspects of water determination in foodstuffs [21],... 

Johansson, E., J. A. Persson C. Albano, 1987. Determination of water content and calorific value of peat by n.i.r. spectroscopy. Fuel 58 1173-1178. 

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