Karl Fisher method

Elemental composition In 82.71%, 0 17.29%. Indium trioxide may be digested with nitric acid, diluted appropriately and analyzed for indium by AA or ICP. It may be identified by x-ray diffraction. The oxide may be heated with excess hydrogen and water formed may be analyzed quantitatively by gravimetry or the Karl-Fisher method. 

Water concentrations in liquid and solid phases were measured by the Karl Fisher method using the Karl Fisher Titrator (Mettler DL 18). Butanol and butyl butyrate were determined by gas chromatography using a 6-ft, 5% DEGS on a Chromosorb WHP, 80/10 mesh column (Hewlett Packard, Palo Alto, CA) and hexanol as internal standard. Acid consumption was monitored by volumetric titration of samples diluted in ethanol employing 0.02 M KOH alcoholic solution and phenolphthalein as pH indicator. Esterification was expressed as molar percent of consumed reactant, according to Eq. 1 ... 

Methods of Analysis. Water Content of Fractions. A chromatographic method was employed using a glass column (6 ft x 0.2 mm ID) packed with Po-rapak QS. The chromatographs used were a Varian 3700 or a Hewlett Packard 5880. Water contents were also determined by the Karl Fisher method by Huffman Laboratories, Golden, Colorado. 

It has been proved in several research papers that water is the most important factor in the component s degradation of ORSs. To proceed with the study, the pharmaceutical formulation was prepared by a pharmaceutical manufacture. The batch was packed in six types of packaging material. After storage of samples for 36 weeks maintained at ambient temperature, at ambient temperature and 76% relative humidity, and at 40°C with 80% relative humidity, analyses of water determination were made at different intervals of time. Water determination was performed by loss on drying at 50°C and Karl Fisher methods. 

The pyrolysis oil is collected at the bottom of the condensation columns, weighed to obtain the wet mass before determining its moisture content (Karl Fisher method). 

Numbers in square brackets indicate water content values measured adopting the Karl Fisher method. 

Benzene (analytical grade) was dried by molecular sieves of 4A size and distillated. N-Polyamine (Aldrich, 98%) was double distillated under vacuum. Purity of the reagents was checked chromatographically. It was 99.95 % for CH3(CH2)2NH2 and 99.98% for C6H6. The content of water was determined by Karl Fisher method It was not greater than 0.01%. 

Numerous methods for the determination of monomer purity, including procedures for the determination of saponification equivalent and bromine number, specific gravity, refractive index, and color, are available from manufacturers (68—70). Concentrations of minor components are determined by iodimetry or colorimetry for HQ or MEHQ, by the Karl-Fisher method for water, and by turbidity measurements for trace amounts of polymer. 

The extraction of phosphates from freshly cut plants containing different amounts of water at the surface of leaves or within other material could be a source of uncertainty in the analysis step. With this in mind, one solution is to freeze-dry the fresh plant material. The dried material can then be milled to a fine powder, and the content of water is determined by the Karl-Fisher method, as modified by Moibroek and Shahwecker. Finally, analyte anions can be extracted from the plant material in accordance with the AOAC method for dried vegetables and flours. " ... 

The Karl Fisher method is recommended for general use in solvents to determine the water eontent. It is not suitable if mercaptans, peroxides, or appreciable quantities of aldehydes and amines are present. Water in halogenated solvents may cause corrosion, spotting, reduce shelf-life of aerosols, or inhibit chemical reactions, thus special method, also based on the Karl Fischer titration, was developed for halogenated solvents. ... 

The water content in the as-received powders is determined by the Karl Fisher method and is generally below 0.1%. 

Moisture. The water content of lecithin products is usually less than 1.0%. As a consequence of lecithin s essentially moisture-free state, lecithins have very low water activity and do not adversely contribute to the microbiological profile of most food systems. Moisture is determined by the Karl Fisher method. A less accurate moisture level can also be determined by azeotropic toluene distillation or drying in an oven at 105 °C. 

Melting point (52) Water determination (Karl-Fisher method)... 

Uses Removal aid, dispersant, emulsifier, wetting agent, penetrant for oil stains Properties Pale yel. cl. liq. sol. in cold water pH 6.5-7.S (1% aq.) 45.546.5 % solids (Karl Fisher method)... 

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