Answer Posted / lalitha
What is the Karl Fischer Reaction?
ROH + SO2 + R’N �� [R’NH]SO3R + H2O + I2 + 2R’N �� 2[R’NH]I +
[R’NH]SO4R
[alcohol] [base] [alkylsulfite salt] [water] [iodine]
[hydroiodic acid salt] [alkylsulfate salt]
The alcohol reacts with sulfur dioxide (SO2) and base to
form an intermediate alkylsulfite salt, which
is then oxidized by iodine to an alkylsulfate salt. This
oxidation reaction consumes water.
The reactive alcohol is typically methanol or 2-(2-
Ethoxyethoxy)ethanol, also known as diethylene
glycol monoethyl ether (DEGEE), or another suitable alcohol.
Classic Karl Fisher reagents contained pyridine, a noxious
carcinogen, as the base. The reagents most
frequently used today are pyridine-free and contain
imidazole or primary amines instead.
Water and iodine are consumed in a 1:1 ratio in the above
reaction. Once all of the water present is
consumed, the presence of excess iodine is detected
voltametrically by the titrator’s indicator
electrode. That signals the end-point of the titration.
The amount of water present in the sample is calculated
based on the concentration of iodine in the
Karl Fisher titrating reagent (i.e., titer) and the amount
of Karl Fisher Reagent consumed in the
titration.
Is This Answer Correct ? | 36 Yes | 1 No |
Post New Answer View All Answers
what is mean by 40 in the dissolution basket mesh size?
In performance Check of GC Why Hexadecane Peak is Considered
what is mean by nitrosamine impurities?
before starting analytical method valodation what you checking? and how giving preference to start validation?
how to get accurate result for Residue on evaporation in purified water
Tell me about analytical method validation in QC
What is the Formula for coreletion coefficient in plhplc calibration
How can I develope method of dissolution by HPLC OR UV
how we can identify the impurity is coming below loq at transfering site?
what is partion and column chromatography
WHICH STANDARD WE USE IN SILICA ANALYSIS IN SILICA-GEL METHOD FOR SOLID SAMPLE
in monograph 7 imp are there but in vendor showing 5 imp do not req to include 2 imp for that what will be justification?
on the basis of bcs class how to proceed the solubility?
which batch require to use for analytical method validation?
identification is for unknown? qualification for known? reporting for LOQ?