Volumetric titration is typically selected for samples in the 100 ppm to 100% water content range, although sample analysis down 10 ppm water is possible. One component Karl Fischer reagents are the most popular as they are the least expensive, and don't always require a special solvent. In one-component Karl Fischer Titration, a titrant with a known concentration is reacted with a sample in a vessel solvent, ultimately consuming the water in the sample.

The titrant contains all the components required for the KF reaction: iodine, base, sulfur dioxide, and a solvent medium. The vessel solvent is chosen to match the sample dissolution characteristics. By measuring the volume of the titrant added, the amount of water in the sample can be calculated. The Watermark product line includes reagents with titer values of 5 mg/mL, 2 mg/mL, and 1 mg/mL, covering an array of applications.

With a methanol-free and pyridine-free formula, Watermark volumetric titrants are suitable for all KF titration samples, even those with aldehydes or ketones.

Not sure which to choose?

Choose a One-Component System if your lab is on a budget, or performs frequent KF titrations. All reactants are in the titrant bottle, and our Watermark non-hygroscopic titrants are designed to be exceptionally stable with a guaranteed shelf life of two years.

Choose a Two-Component System if you need a higher degree of accuracy, faster titrations, or need to standardize less frequently. The lowest strength available is 0.5 mg/mL and is designed for applications with minimal sample, or very low water content.

Coulometric titration is typically selected with a water content of less than 1%, although samples with water content up to 5% are possible. Anolyte and catholyte choices are based on the sample matrix, which in turn influences generator choice.

Watermark reagents offer the best value and performance for Karl Fischer titration in the industry. With extended shelf life, rapid moisture determinations, and a stable end-point, it is evident that Watermark outperforms the competition. Watermark, by GFS Chemicals, is specially formulated to provide the ultimate in analytical performance.

Standardization of a Karl Fischer titrant is necessary to determine its water equivalency. GFS Chemicals manufactures a broad range of reference materials, including primary standards in our Columbus, Ohio facilities.

Water standards are delivered in boxes of 10 single-use ampoules, and come with a 5-year shelf life. Watermark water standards are methanol-free and can be used for all applications. All standards come with a Certificate of Analysis (COfA), are scrupulously tested in our ISO/IEC 17025 accredited management system, and are NIST traceable.

Solid standards, including sodium tartrate and potassium citrate, are also available.

The Karl Fischer reaction is pH dependent. Most of the Watermarks titrants and solvents are buffered to counter samples that cause small pH changes. If the sample causes the pH to change outside the required 5 to 7.5 range, side reactions and slow kinetics are likely to occur.

To counter the effects of samples with extremely high or low pH values, add a buffering material to adjust the pH back to the optimal pH range.

GFS Chemicals specializes in the manufacture of anhydrous magnesium perchlorate which is an excellent drying agent for air and gases. KF titration systems require protection from atmospheric moisture. We offer many options including molecular sieves, indicating silica beads, drierite and calcium-based desiccants.

Compare our prices and see if we can save you money over your current supplier.