Development of Karl Fischer Reagents

H2O�I2�SO2�3Base�CH3OH � 2Base � HI�Base � HSO4CH3
2
Note: Base = Amin. "Base" is sometimes shown as RN.
Characteristics of the Karl Fischer Titration Method
The measurement of moisture content using Karl Fischer reagents is
superior to other methods such as loss-on-drying, distillation and infrared
absorption, or to electrolysis and other electrical methods, for the following
reasons:
(1) The absolute amount of moisture can be determined without a
working curve (in the case of coulometric titration). Moisture
content can be determined accurately, even where moisture is
present at levels of only a few ppm.
(2) Measurements can be taken over short periods of time.
(3) Measurements can be taken using small samples (from a few
mg to a few gm).
(4) The method can be used with liquid, solid and gaseous
samples.
(5) The method is suitable for unstable substances that can alter
when heated.
Mitsubishi Chemical Corporation and Karl Fischer Reagents
Mitsubishi Chemical Corporation recognized early on the advantages of the
Karl Fischer reagent, when it was introduced into Japan in the postwar era.
The company began to investigate this in 1950. It subsequently developed
Karl Fischer reagent SS, a single solution with stable titer that could be used
by anyone in factory research or analytical laboratories. It also developed
and supplied a variety of dehydrating solvents for use with various types of
samples. In addition, Mitsubishi Chemical Corporation developed simple
methods for measuring the moisture content of various substances and
manufactured products. With each new methodology, the company
endeavored to promote the use of the Karl Fischer titration method through
papers for scientific symposiums and society journals (about 60 to date).
In 1985, Mitsubishi Chemical Corporation developed a new Karl Fischer
reagent without the pyridine odor. The new pyridine-free products were
named the "S-Series". The company continues to respond to the needs of its
customers. In 1992, it added the X-Series products, which do not contain
carbon tetrachloride or chloroform, to its range of coulometric reagents.
This manual has been written to provide basic information on Karl Fischer