Karl Fischer Reagents

GFS Chemicals manufactures the Watermark® Karl Fischer line - one of the largest selections of Karl Fischer reagents on the market and has the internal technical expertise to meet your needs. From volumetric and coulometric Karl Fischer reagents to certified water standards, GFS Watermark® Karl Fischer Reagents are in stock and available to ship. GFS offers both pyridine and pyridine-free solutions. Our Watermark® Karl Fischer coulometric reagents have a water capacity, in excess of 1000 mg of water/100 ml charge.

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Volumetric Karl Fischer Reagents

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 KF 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.

Titrant Standardization and Instrument Check Materials

Standardization of a KF 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 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, are manufactured to ISO 17025 standards and are NIST traceable
  • Solid standards, including sodium tartrate and potassium citrate, are available.

Watermark® One-Component Titrants & Solvents 

  • With a methanol-free, pyridine-free formulation, Watermark® volumetric titrants are suitable for all samples that can be analyzed via KF titration, even those containing aldehydes or ketones. Choose a one component titrant if your lab is on a budget, or your lab performs frequent KF titrations.

Watermark® Two-Component Titrants & Solvents

Choose a two-component system if you want faster titrations, need a higher degree of accuracy, or want to standardize less frequently. Wondering how two component and one component titrants differ? The reactants are SEPARATED between the titrant and solvent. In a one component product, all reactants are in the titrant bottle. Watermark® non-hygroscopic titrants are designed to be exceptionally stable with a guaranteed minimum shelf life of 2 years. The two-component line also offers a titrant with the lowest titer strength available: 0.5 mg/mL. Designed for applications with minimal available sample, samples with very low water contents.

Coulometric Karl Fischer Reagents

Coulometric titration is typically selected for samples with a water content of less than 1%, although samples with water contents 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 on the market today. With extended shelf life, rapid moisture determinations, and a stable end point, it’s easy to see why Watermark® outperforms the competition. They are specially formulated to provide the ultimate in analytical performance.

Karl Fischer Buffering Materials

The Karl Fisher reaction is pH dependent. Most of the Watermark® 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 that will adjust the pH back to within the optimal pH range.

Desiccants & Drying Agents

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.