According to KF principle is medium should need lower alcohol or organic solvent and the lower alcohol is methanol. The iodine reacts with water, and the consumed iodine value is water content. All drugs are polar in nature so easily dissolve in methanol so used to neutralize kf reagent.
Which electrode is used in Karl Fischer?
Double Platinum Electrode
The most advanced KF titration technology uses a double platinum electrode for electrochemical indication of the endpoint, but visual and photometric indicators are also used.
Why do we use sodium tartrate in Karl Fischer?
The volumetric standard for Karl Fischer titration is sodium tartrate dihydrate. It is stable and non-hygroscopic, under normal conditions. Sodium tartrate dihydrate has a 15.66% stoichiometric water content and is primarily used in volumetry to measure the titer.
What is the use of Karl Fischer?
Karl Fischer titration is a classic titration method in chemical analysis that uses coulometric or volumetric titration to determine trace amounts of water in a sample. It was invented in1935 by the German chemist Karl Fischer.
Why DST is used for KF calibration?
DST is the primary standard and it is stable up to 150 degree Centigrade. It releases free water molecules easily when reacts with the KF reagent. This DST has 15.66% water molecules so we can easily calculate and standardize the KF reagent. We use the factor of DST the compound which has less than 1% of moisture.
What is a formula for KF standardization?
KF standardization with water: Formula = wt. of water x 1000/KF titer value.
What is the meaning of Karl Fischer?
Definition of Karl Fischer reagent: a colored solution of pyridine, sulfur dioxide, iodine, and anhydrous methanol that reacts quantitatively with water to form a colorless solution and is used to determine the amount of water in numerous substances.
What is the factor in Karl Fischer?
The water equivalence factor F, in mgs of H2O per ml of reagent, is calculated according to the formula 0.1566 x w/v,
where
W is the weight in mgs of sodium tartrate
V is the volume in ml of the reagent.
Each mg of sodium tartrate is equivalent to: 2H2O 36.04.
What are the advantages of Karl Fisher water determination?
The advantage of the Coulometric Karl Fischer method is the capability to accurately measure small amounts of moisture. The sensitivity of these instruments is as low as 0.1 microgram (μg) of water. This method is normally used for moisture content below 1% or for samples where the moisture is less than 200 micrograms.
What are the major disadvantages of Karl Fischer titration?
The major disadvantage of Karl Fischer is that the KF reagents have water equivalents that change over time, and they must therefore be regularly calibrated when the use of the volumetric method. Manual volumetric titration consumes more solvent.
How do you calibrate KF?
Weigh accurately about 0.005 to 0.05 gm (5 to 50 mg) of water with the syringe and enter the weight in gram. Press the “RUN” key so that red light will glow on “BUSY” position. Again press the “RUN” key so titration will start.
How do you calculate KF?
Divide the freezing point depression by the molal concentration so you have: Kf = delta Tf /cm. Insert the values for delta Tf and cm. For instance, if you have a solution with a molality of 0.455 which freezes at 3.17 degrees Celsius, then Kf would equal 3.17 divided by 0.455 or6.96 degrees Celsius.
What is the formula of factor KF?
The water equivalence factor F, in mgs of H2O per ml of reagent, is calculated according to the formula 0.1566 x w/v, where W is the weight in mgs of sodium tartrate and V is the volume in ml of the reagent.
What is the importance of water determination?
Superior quality of water is crucial to the economic, health, and social well-being of the people. Monitoring the quality of your water and testing it regularly is very important to maintain reliable and safe water sources and eliminate the potential health risks related to water contamination.
What is Karl Fischer reaction?
Karl Fischer titration is a widely used analytical method for quantifying water content in a variety of products. The fundamental principle behind it is based on the Bunsen reaction between iodine and sulfur dioxide in an aqueous medium.
What is the limit of KF factor?
The relative Standard deviation between two average KF factors of water and DST determined consecutively should not be more than 3.0 % [Average of two factors (2 with water and 2 with DST) to be considered for calculation.]
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