As mentioned aforehand, the reagents based on the Karl Fischer method are to be divided into two different groups. On the one hand, there are so-called one-component reagents which are particularly suitable for the volumetric Karl Fischer titration of water. They include all components such as iodine, sulfur dioxide and imidazole (dissolved in alcohol). Great popularity among users experiences this type of reagents especially because of its easy handling since the components are already mixed to a singular solution. On the other hand there are two-component reagents which are build up slightly differently. Just like the one-component variant, they contain all the needed ingredients, however, divided into two separate solutions. This consists of a solution of sulfur dioxide, imidazole and methanol and a titrant - consisting of iodine and a water equivalent titrant. Both solutions are needed for the volumetric Karl Fischer titration and because of the separate solutions, the two-component version is slightly more complex.