Aquastar¨ One Component Volumetric Karl Fischer Reagents
When water content of the sample exceeds 1%, volumetric determination is usually the method of choice. There are many choices of reagents to perform water determination using the Karl Fischer titration method. The reagent initially developed by Karl Fischer was a one-component reagent; that is, it included all of the basic components for the reaction. Over the years research has produced formulations with different bases, mostly to avoid the objectionable pungent odor of pyridine. These pyridine-free formulations, which buffered in a more favorable pH range than pyridine, also made faster, more accurate titrations possible. Similarly, methanol has been replaced by other less toxic alcohols such as Diethylene glycol ethyl ether (DEGEE). As a consequence, Karl Fischer reagents with many different formulations are available. The new Aquastar CombiTitrants are non-toxic formulations and they contain the reactive components SO<sub>2</sub>, I<sub>2</sub>, and base - all in one solution. The advantage of the one-component Karl Fischer reagent system over the two-component system is that during the titration, SO<sub>2</sub> and base are always being added so a larger number of titrations can be performed without changing the solvent in the titration cell. There are three CombiTitrants with titers of 1, 2, and 5mg H<sub>2</sub>O/mL to cover a wide range of titration applications. Aquastar CombiTitrants are best used in combination with Aquastar CombiMethanol. Aquastar CombiMethanol is anhydrous methanol with strictly controlled water content and trace impurity limits that is the solvent of choice for most volumetric Karl Fischer titrations. EMD Chemicals also offers several solvents for different sample types, including oils and fats. <em>Aquastar CombiTitrants and CombiMethanol are compatible with all brands of titrators.</em> Recommended Titrator: Aquastar AQV33 Volumetric Karl Fischer Titrator.