Karl Fischer reagent stabilized

The stability of the reagent is much improved by replacing MeOH with Me0CH2CH20H, and this forms the basis of the present-day Karl Fischer reagent. 

The original Karl Fischer reagent prepared with an excess of methanol was somewhat unstable and required frequent standardisation. It was found that the stability was improved by replacing the methanol by 2-methoxyethanol. 

Karl Fischer Reagent, single solution stabilized, methyl cellosolve as solvent, eg, catalog No So-K-3, diluted to about 2mg/ml titer with methyl cellosolve or a commercial diluent, eg, catalog No So-K-5 of Fisher Scientific Co... 

Commercially available Karl Fischer reagent is stabilized and can be obtained free of pyridine, which is toxic. It can also be prepared in the laboratory however, this requires the use ofS02, a poisonous, liquified gas. 

For volumetric analysis, the classical Karl Fischer reagent consists of I2, SOi, pyridine, and anhydrous methanol or another suitable solvent. The reagent decomposes on standing and must be standardized often. Stabilized Karl Fischer reagents are available commercially from several suppliers. For ketones and aldehydes, spe-... 

Karl Fischer Reagent Ethylene Glycol Monomethyl Ether Solution, stabilized, containing pyridine, (1 mL = S mg of water)—Fresh Karl Fischer reagent must be used. Must be used with solvent in 7.6.1. 

Pyridine combines with both products. A Karl Fischer titration unit is available (A.H. Thomas Co.) for detection of the end point by means of platinum electrodes and a pH meter. A.H. Thomas Co. supplies two solutions which are to be mixed (I2 in CH3OH and SO2 in pyridine) as well as a stabilized single solution (also available from Fisher and MCB). Methyl Cellosolve has been suggested as solvent in place of methanol, A similar reagent utilizing a solution of bromine and sulfur dioxide in chloroform has been described. ... 

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